At my home mountain (Okemo), they say they require a park pass, but there's never a person attending the enterance to the large sized park. I haven't even re-upped my pass for this season and have never been questioned. Plenty of gapers are making it in and just hanging out on the landings causing trouble for everyone who is actually trying to ski and improve.
I'm all for park passes, but if we just let everybody get them, or let people slip into the bigger parks without getting checked, then there's really no point. I wish there were some way that the mountain could feasably test a skiiers ability to ride the features, rather than their ability to pay a fee or answer five ridiculously easy safety questions before issuing a park pass. Otherwise our parks are just going to remain crowded with the kind of people who make it dangerous for themselves and anyone legitimately trying to progress.