The folk police are like many other police. I'm a vegetarian but a few times it's been too rude not to eat what was served, and I suppose the vegetarian police could bust me. But I think I prefer being tainted to being perfectly rule-bound.

Seinfeld had a lot of fun with situational rules and with characters becoming the "police" of various situations, (is soup a "meal"?) or criminal masterminds of others (how to date your girlfriend's room-mate). It was a good running joke formula that sometimes involved actual police characters debating things like backing-in to park vs. pulling-forward. It's a good renewable source of humour because we are all silly like that one way or other.

I take all sorts of filing systems to be filing systems, music isn't about what folder you'd put it in. Young people and students can get very caught up in all that armature, and suppose it improves them, somehow. But it is fun and interesting to think of what is essentially this or that, how it works, its psychology, what the gist of style is. Greg's comment reminds me of the Art-rock I grew up hearing, which seemed to stop being rock at all somewhere along the way. People always laugh off the What is Folk question, but I think it's fun as long as there are interesting, thoughtful, or even surprising answers. Or funny arguments.