I recently played with 2 players in ARAM that threw themselves to the enemy team while "doing" something. We lost fast. I ask to report those two and they said that it's not "intentionally" feeding since they were attacking, therefore Riot won't do a thing to them. Walking up to the enemy while activating abilities in a 1 v 5 doesn't excuse you from being reported of feeding, does it?
It's very difficult to prove the intent, but that doesn't mean they'll get away with it. Just report them and leave a description of what they were doing and move on. I also recommend not queueing for another match immediately, to reduce the chance you get paired with them again.
This board seems to be obsessed with the idea that trolling and intentionally feeding is somehow ridiculously easy to get away with, and being upset is all that gets punished. If you look at these boards, you'll see tons of feeders and trolls getting busted.
Point being, if these idiots are trolling and feeding in more than just a couple of games every blue moon, then they'll get punished.
