I believe the way the OSM community goes about "enforcing" the license is lacking on many fronts, which I suspect is a sentiment shared by many (but not most) mappers. I have a proposal for addressing the problem a part of which is mass identification of the users of the tiles and the offenders, but also introduction of a (hopefully) community-acceptable way to enFORCE the license.

As a first step I wanted to get at least rough numbers about the scale of the offenses. I will present the proposal either on the legal talk list or write a blog post.