Just my opinion (two cents worth) here, mind you, but I don't really see there being such a thing as "mode invasion" in and of itself, since you need to be invited in to private groups. On the one hand you have insufficient scrutiny and consequences, and on the other you have meta-gamers seeking cheap thrills and childish notoriety.
It's a bit of a silly mess and I'm certainly glad it isn't something I'd unwittingly subject myself to nor take part in.
I understand some people play this game for different reasons than I do, and to some of them, this sort of meta-gaming doesn't seem to register on their radars. It's just playing the game to them.