Yes, I had a look at that thread, seemed to be the usual sort of discussion of whether a group can be classified as bluegrass or not. Don't see where "police" comes into it. People often vaguely wonder if spiders are a kind of insect, or if sponges are plants or animals: are we to call such people "biology police"?
    Classification is always an interesting and difficult area, but not, to my way of thinking, very similar to criminal investigation and law enforcement.