This guy apparently just gamed himself a Taxonomist badge by adding the completely useless "regex-literal" tag to just enough questions. I've been wiping them up again, and it occurred to me to wonder if that will have any effect on him. Will he lose the badge because it's not on fifty questions any more? Probably not, but could it be made to work that way? Should it?
I've seen several mentions of this problem, particularly in regards to the Taxonomist badge, but nothing was ever resolved because nobody could point to a real-life example. Well I don't think there can be any doubt that this guy is gaming the system. And it's working, too: as of this moment, he does have the Taxonomist badge, and it was awarded for the "regex-literal" tag.
I'm not interested in punishing the guy, but I would very much like to discourage this kind of thing in the future. He put a lot of work into this, and I'm sure he wouldn't have done it if he had known the badge was likely to be taken away again very soon. But, as much as I like the idea of perishable badges, it seems like there should be a better mechanism in place already; I just don't know what it is. How are we supposed to flag this kind of thing for moderator attention? He's not doing it by posting questions or answers, just editing tags.