Which is exactly why you're able to speed with impunity, even if you receive a ticket for it?

Most places do not make the rules unclear and many rules brought up in the subthread, e.g. hydrants and parking near an intersection, are well known and common among the states.

Look, I'm not saying that basically giving everyone a month with no warnings and then going out in force isn't a crappy thing to do. I'm just saying that that's not entrapment, nor is an an awful thing for the police to do, even if there are nicer ways to do it, e.g. giving notices on windshields for the first week of the semester and afterwards being issuing tickets.