I've found myself in the Low Priority Queue once... because my ISP is terrible, as my internet connection has the annoying habit of just painly cease functioning for 10-15 minutes, completely at random, netting me a few abandons. It was only 24 hours though, so I just found other things to do in the meantime. Such as calling my ISP and yelling at them for being terrible.
Never gotten any sort of repercussion for being an asshole, because avoiding such repercussions is as simple as not being an asshole (if you absolutely have to be an asshole, being a polite one will dramatically increase your chances of getting away with it). The only reports I've ever gotten (not that any of them have gone anywhere) are from people who are unaware of their own asshattery, thinking that I'm the culprit when they are the people who are calling people idiots, and the people who somehow believe that being bad at the game is grounds for reporting.
Speaking of which, I cannot be the only one who has an aneurysm at the last one. I have never, ever managed to deduce the logic behind believing the report system is there to remove poor players from the game. Is that a system that's implemented in another MOBA? Or are people just that maliciously incompetent?