I've only stumbled on someone taking Chaotic Insane before I did ONCE. Which is impressive, considering it's a variation on "chaotic nutzo" which is a bit of an inside joke at our table. I was more than a little miffed since finding an SN that ISN'T taken on an MMO is a feat.
But we have people copying other's names on my horse sim aaaaall the time, especially since there isn't a filter stopping anyone from sharing names. This would be all fine and dandy if they didn't try and pass off as being a spare account for a well-known player, mods, or the admin. Or just random players that pissed them off, copy their name, and then spam chatrooms with obscenities trying to pin it on their target like we can't see IP adresses. *eyeroll*
As far as people who don't post... Well, if my dad wasn't here I'd JUST lurk, and even then I'm still lurking probably twice as much as I'm actively posting. I'm surprised Doomy's posted as much as he has since he's usually a grade A lurker. However, stealing other people's SNs and just lurking, while not as bad as trying to impersonate that person, is infuriating. There'd be some shit flying if someone tried to take Chaotic Insane (or black magius/black robe) anywhere related to where I'm actually kinda known (horse sims/horse art community on dA).