Streetwear pop-ups have become cultural phenomena, drawing massive crowds of younger, energetic and eager followers to get their hands on exclusive merchandise. The energy at these events can be electric, but as recent incidents in London and Perth have shown, it can also spiral into disruption. What drives this kind of behaviour? Psychological principles such as deindividuation, collective behaviour, and social proof offer valuable insights into why crowds become unpredictable. Understanding these dynamics is important for event organisers looking to ensure safety and control. Why are we talking about event organisers when discussing guerrilla promotion tactics, well lets continue the discussion.

Streetwear brands rely heavily on the principle of scarcity, a psychological concept studied extensively by Cialdini (1984). The idea is simple: when something is perceived as rare or exclusive, people instinctively desire it more. Social media exacerbates this effect, creating an urgency that fuels massive turnouts at pop-ups. When a brand teases a surprise drop or a free giveaway, people rush to participate, often disregarding logistical or safety concerns. This is precisely what happened in London when thousands of attendees overwhelmed the space, leading to dangerous overcrowding.

One of the key psychological mechanisms behind disruptive streetwear pop ups could be deindividuation, a phenomenon in which people in large groups lower their sense of individual identity and responsibility. Research by Zimbardo (1969) suggests that anonymity within crowds can reduce accountability, making individuals more likely to act in ways they might otherwise avoid. The sheer size of these gatherings provides a sense of safety in numbers, which can further lower inhibitions by reducing the perceived risk of punishment or arrest. This feeling of collective security emboldens individuals to engage in behaviours they might hesitate to attempt alone. However, Reicher (1984) offers a different perspective, arguing that crowd behaviour is often guided by shared social identities rather than sheer loss of control. This perspective is particularly relevant in the context of younger attendees, who may seek to establish their identity through group belonging and shared experiences, further reinforcing the collective mindset at these events. This suggests that attendees in London may not have been simply acting impulsively but were instead influenced by a collective anti-authority sentiment or a sense of dominance over the space. Moreover, any residual fear of consequences they might have felt could have heightened their adrenaline, intensifying their actions and contributing to the escalating crowd behaviour.

Similarly, collective behaviour plays a role. When individuals see others engaging in extreme behaviour, they are more likely to follow suit. The Perth incident, in which a store owner encouraged customers to “rob” the store as part of a promotional stunt, highlights how group excitement can quickly escalate into a crowd incident where risk of injuries increased. More recent studies (Drury & Reicher, 2000) argue that crowds don’t act irrationally but are shaped by pre-existing social norms and the influence of leaders. The messaging from the store owner in Perth didn’t just inspire recklessness—it set an expectation that rule-breaking was acceptable in that context, which others quickly adopted.