Earlier quoted context omitted.
That's not entrapment. Entrapment is the state coercing someone to do something they would not do under normal circumstances. It sounds to me as if these people are illegally parking under normal circumstances. The rules about curbs, hydrants, driveways, &c are well known and common enough between every state that there is no excuse that they weren't aware this was illegal.
A trap is something easy to get into but hard to get out of. They made the parking rules unclear and never enforced them then cracked down brutally.
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.