A few months after the introduction of the smoking ban in England, these warning signs started popping up in a few underpasses around where I live. This one, near the local college, could have definitely been the result of students retreating to this underpass to smoke, having banned from smoking in campus. 

For every piece of new rule-making (or tightening of enforcement of existing rules), what is the potential for simply transferring the undesired behaviour away from the rule-maker’s backyard, into more obscure areas? And how often is this potential taken into account during the rule-making process?