We provide evidence for a beneficial welfare impact of a policy targeted at strengthening victim precaution. Regulation made application of the electronic engine immobiliser mandatory for all new cars sold within the European Union. We exploit the regulation as source of exogenous variation in use of the anti-theft device. The device reduced car theft by an estimated 40%, accounting for both the protective effect on cars with the device and the displacement effect on cars without the device. 34 cars need to be fitted with the device (at a per unit cost of 50 euros) to avert one theft.