Dude, I'm pretty sure that's not going to happen anytime soon, trust me as I know a bunch of people that has complained to Zise about it, in fact they did reset all the cyan names as there were too many users running around with them, but they never cared or did anything about the people running around with bigger avas (For example, I lost my Cyan name after about 5 months time or so, when I only should have had it for once, but they never touched my ava). The only reason I lost mine was because of a certain someone complaining me in for having it when the time I was entitled to it had expired long time ago (not that I really cared or anything, as I was thinking of changing ava, but didn't as I knew I would lose my bigger one).
So unless someone goes around "reporting" everyone that shouldn't have bigger avas, they won't lose it in the nearest future. The only thing that's going to stop them at the moment is if they decide to change their avas.
So that's kind of the only downside of it as you will have to keep that ava forever, or else you will go back to normal ones.