For decades, event organisers and policymakers have operated under the belief that visitors will naturally extend their experience beyond the event site—strolling into local cafés, browsing independent shops, or soaking up cultural attractions. It’s a comforting narrative, but the Cambridge Half Marathon study soundly debunks it.

Despite the event’s central location and clear access to the city’s iconic heritage sites, less than 8% of non-local visitors ventured beyond the event zone. Instead, most arrived, ran, recovered, and left—all within the carefully bounded footprint of the event. These findings are not an outlier; they mirror patterns seen at Olympic fan zones, music festivals, and sporting events globally, where temporary urban enclosures concentrate visitor attention and restrict movement.

The implications are serious. Cities justify major events on the basis of wide-reaching economic benefits. Yet if the vast majority of visitors don’t move beyond the barricades, those promises ring hollow for local businesses, especially those outside the immediate event zone.

This isn’t just a missed opportunity—it’s a planning failure. Events like the CHM create what Duignan et al. call “cities within cities”—experiential bubbles that override normal urban flows. The event zone becomes the destination. And without deliberate interventions, there is little incentive—or information—pushing visitors to explore further.

Crucially, the data shows that even among first-time visitors, who might be expected to exhibit curiosity, engagement beyond the zone was limited. The myth of automatic spill-out is not only unsubstantiated, it’s actively undermining efforts to use events as tools for distributed place-based development.

To move forward, stakeholders must abandon this passive assumption and adopt a more proactive stance. Visitors don’t spill out unless nudged, guided, or inspired to do so.

Understanding why some visitors venture beyond event zones while most don’t requires a closer look at who they are, how they travel, and what shapes their choices. The Cambridge study’s strength lies in its ability to statistically dissect these patterns.

The analysis revealed several key predictors of exploratory behaviour. Male visitors were significantly more likely to engage beyond the event zone than female visitors. Those travelling in groups—especially with family or friends—were also more inclined to explore the city, suggesting that collective decision-making encourages broader engagement. Additionally, those who rated the event as good value for money and were satisfied with food and beverage options were more likely to stay longer and move beyond the designated space.

These are not marginal insights. They reveal that simple tweaks in visitor experience—like offering higher quality, better-value food and clearer communication—can have a measurable impact on post-event engagement.

Meanwhile, the qualitative data uncovered deeper behavioural motivations. Visitors who explored often cited a desire to celebrate, unwind, or avoid post-race congestion. Others used the warm-down as an opportunity to walk, stretch, or discover. These were not accidental spill-outs—they were driven by individual preferences and contextual nudges.

On the flip side, exhaustion, discomfort, and poor planning emerged as strong deterrents. Many cited their physical state post-run as the primary reason for not exploring—highlighting how physiological factors can influence economic outcomes. Others simply didn’t know what else was available or felt there was no time to linger. This points to a failure not of interest, but of preparation and facilitation.

What emerges is a clear conclusion: engagement beyond event zones is not random. It’s shaped by a blend of demographic, psychological, and logistical factors. Understanding these dynamics is essential for designing interventions that work. If we want visitors to behave differently, we need to understand what drives—and hinders—their decisions.

If we treat cities as dynamic systems, then events temporarily rewire how people move through them. Nowhere is this more apparent than in the design and execution of event zones. These are not neutral spaces—they are purpose-built, bounded, and highly curated environments designed to direct behaviour, often with unintended consequences.

At the Cambridge Half Marathon, the event zone at Midsummer Common functioned as a self-contained bubble. It provided everything: start and finish lines, food stalls, medal collection, sponsor activations, toilets, and meet-up points. The result? There was little practical or psychological reason to leave. What’s more, transport and parking were concentrated around the site—funnelling visitors in and out through a single access point.

This concentration is a feature, not a bug. Organisers often design event zones to simplify security, focus crowd management, and ensure commercial exclusivity for sponsors. These zones are immersive, energetic, and convenient. But they’re also isolating. The more effective they are at creating a self-sufficient event experience, the less likely visitors are to interact with the surrounding community.

The physical design is reinforced by symbolic cues—barriers, signage, staff direction—all of which send an implicit message: stay here, this is where the action is. These soft signals shape mental maps of the city, particularly for first-time visitors who often rely on environmental clues to decide where they can (or should) go.

Moreover, the temporal structure of the event discourages linger time. Races start early, and many visitors arrive just in time, perform, and leave. Without dedicated programming before and after the main event, there is little invitation to explore further.

The broader insight is this: spatial and temporal containment is not neutral. It has distributive consequences. It determines which businesses benefit, which neighbourhoods are included, and who feels welcome. Until organisers and city planners treat event design as an exercise in urban inclusion—not just logistics—spill-out will remain the exception, not the rule.

When visitors do explore beyond the event zone, it’s often because something—or someone—nudged them to. But as the Cambridge study reveals, these nudges are mostly incidental: a sunny day, a missed bus, or the need to warm down. The opportunity lies in converting this serendipity into strategy.

Behavioural economics tells us that small changes in context can lead to big changes in behaviour. Applied to event planning, this means organisers and destination managers can influence visitor choices through intentional design. Yet, in Cambridge, these nudges were minimal and poorly integrated. For example, the CHM’s “unlock discounts” campaign—intended to encourage spending in local businesses—had limited uptake, mostly because it lacked visibility, clarity, and integration into the event journey.

Contrast this with more effective strategies in other events. The London Marathon encourages participants to celebrate in nearby pubs by partnering with local businesses and promoting post-race deals in the race guide and on social media. At the Rio 2016 Olympics, serendipitous engagement emerged through live cultural programming in public transport zones, extending the event experience and drawing visitors into surrounding districts.

In Cambridge, visitors reported wanting to explore—but didn’t know what to do, where to go, or how to fit it in. This is a failure of communication as much as infrastructure. Pre-event packs didn’t highlight cultural routes, nearby landmarks, or tailored itineraries. There was no signage directing foot traffic beyond the event bubble, nor were there “cultural hosts” or volunteers encouraging post-race discovery.

Nudging isn’t about forcing people to act—it’s about making the preferred choice easy, obvious, and rewarding. For example, including curated walking routes from the event zone, timed events post-race, or incentives linked to local landmarks could subtly shift behaviour.

In short: visitors are willing. But willingness without opportunity and guidance leads nowhere. With smart design, nudging can bridge the gap between attendance and engagement, and transform events into real engines of local benefit.

For decades, city officials and event organisers have clung to a comforting myth: that visitors will naturally spill out from events into surrounding areas, benefiting local businesses and enriching their experience. The Cambridge Half Marathon data shatters this illusion.

Across four years and over 6,000 survey responses, the evidence was clear—just 7.6% of non-local visitors engaged beyond the event zone. Even with a prime location in the heart of the city, the majority of participants arrived, raced, and departed. The anticipated halo effect never materialised.

Why does this assumption persist? Perhaps because it feels intuitive. After all, large crowds create energy, and surely some of that should leak outwards. But this intuition ignores how event structures actually shape behaviour. As shown earlier, spatial containment, lack of information, fatigue, and rigid scheduling combine to stifle exploration.

The danger of the “natural spill-out” myth is that it creates complacency. If organisers and city stakeholders believe benefits will happen automatically, they don’t plan for them. Local businesses are encouraged to prepare for extra trade that never arrives. Residents expect vibrancy and footfall, only to experience disruption and exclusion. This damages trust and undermines long-term support for events.

The Cambridge case is not unique. Studies from Olympic Games, fan zones, and festivals reveal similar patterns. Unless a deliberate and coordinated strategy is in place, most visitors won’t stray far from the event perimeter. And yet, few cities seem to have fully internalised this.

Let’s be clear: the problem isn’t events. It’s the faulty assumptions underpinning how we design and integrate them into city life. The Cambridge Half Marathon shows us that demand for exploration exists—but it needs to be enabled, encouraged, and rewarded.

Discarding the “natural spill-out” narrative is not a loss—it’s a turning point. It invites a more honest, evidence-based approach to event planning. One that treats visitor engagement not as an incidental bonus, but as a measurable outcome that can—and must—be designed into the event from the outset.