I was recently browsing tags when I entered "protect" in the tag search field. It came back with three results:
Not a single one of them has a wiki description. To me, this makes correct use of the tag more difficult, and will likely relegate the tag to never having many questions attached to it.
Is this useful? Shouldn't a wiki description be required when creating a tag? Mind you, I can't remember if I've ever created a tag, so I don't know how difficult adding such a requirement would be. But I think the requirement would improve the tagging system. Only the original creator of the tag can say exactly what he means it to be used for.