What can public authorities do in order to promote regulatory compliance? This paper argues that understanding the compliance motives is key to any enforcement strategy. Simply stepping up the enforcement effort or stiffening penalties is – most of the time – quite ineffective. Especially attempts at engineering criminal law rules to achieve a heightened deterrence effects will generally be ineffective, social science research suggests. And – much in the same vein – raising administrative enforcement efforts does not automatically raise compliance rates proportionally. There is not a one-on-one relation between enforcement effort and compliance outcome, although this idea seems to be underpinning a lot of present-day enforcement strategies. Enforcement efforts are but one of the many norm-support cues to comply. Recent research rather suggests that a sort of bandwagon-effect exists as regards regulatory compliance. Compliant behaviour, or enforcement activities that reminds us of (or merely point out) the existence of a norm, prompt (more) compliant behaviour. Designers of enforcement strategies need to keep this in mind.