I have yet to see anyone abuse them in my games, regardless of how poorly things are going. I know there were a fair number of people worried they would be used to grief and harass, much like the "missing" ping, but that hasn't been my experience.
What have you seen?
I think I've seen 2 instances where they've been used to bm. I've seen a few instances where they're used in place of "gj". Otherwise, I think they're ok. Not something I'd look to invest much money into.
I mostly see them popped after a won team fight or during a game where one team is winning in a lopsided manner.
They sting about as much as flashing a mastery.
