BACKGROUND: Prohibition-based drug policies such as recent UK draft legislation on recreational drug possession assume expanding police powers will deter use and thereby reduce harm. In fact research suggests punitive policing harms PWUD (people who use drugs) in recreational contexts by incentivising behaviours with lower legal but higher health risk. Although some vectors of this harm have been well researched (notably dog-assisted searches at festival gates), others are less understood. This article aims to help elucidate them by examining how enforcement strategies impacted participants' ability to enact 'responsible drug use' at events.

METHODS: An ethnographic study of volunteer drug crisis care ('psy-care') projects in three contrasting policy regimes comprised 52 days of participant observation, 23 care practitioner interviews, and a qualitative survey of 54 festivalgoers. Thematic analysis was conducted in NVivo within a grounded theory framework.

RESULTS: Although harm reduction-based practices were preferred by holders of the 'responsible drug use' value system and enacted whenever policy allowed, heavily policed settings disincentivised them or rendered them impossible while favouring medically riskier behaviours with lower legal risk. Confiscation at gates negated the risk mitigation effects of pre-measured, tested 'stashes'. Information-rich transactions with accountable dealers became unfeasible, while hasty, anonymous transactions appeared safer. Drug checking services (DCS) were rare, while informal sample checks involved legal jeopardy. Vigilance for police undermined efforts to cultivate a 'set and setting' conducive to unproblematic drug experiences, while both uniformed and undercover policing obstructed access to formal and informal crisis support.

CONCLUSIONS: This article shows that tough policing incentivises risk-taking even among those for whom 'responsible drug use' and harm reduction are strongly held values, illustrating the impact of policing-related perverse incentives on PWUD in recreational settings more generally.