Babies in ARAM.
I know this is a long-standing issue, ever since ARAM wasn't even a legit game mode... but I've ran into this so many damn times today that I'm fed up with it.
I absolutely HATE IT when you queue up, someone rolls a champ they don't like, then they dodge. Like, seriously, come on. The point of the goddamn game mode is to play a random champion, not to play who the hell you WANT to play in a scenario where there's constant teamfights. Riot even went out of their way to introduce the re-roll system to try and sate those people... but I guess that's just not good enough? They can't stand playing a few games as randoms just to get those rolls back?
All in all, there HAS to be a way to make LeaverBuster catch people who dodge queues, not just people who drop from games. Put them all in a pool of people who constantly dodge. See how they like getting someone good, or having a good team comp in Ranked, and then having someone pissy leave because they didn't get mid.