A live in game report function would be able to ban players in game and if they are 0 cs just trolling potentionally kick out these players from the match as they are just assisting enemy team.
Master Yi 7/15/5 vs Warwick 12/5/9 You sure you want Riot to decide which one of you was trolling?
Olaf 2/14/1 vs Master Yi 7/8/8 You sure you want Riot to decide which one of you was trolling?
Master Yi 0/8/1 vs Rengar 0/1/0 This one ok the Rengar was bad. But you were worse...
Master Yi 7/14/7 vs Udyr 2/10/1
Public announcement, if this is happening too much. THEN PLAY DRAFT.
????????? And let you 4v5? Smart.
Wait a minute! My supports usually have sub 10 CS if i'm being lazy in norms! Would that mean i'm trolling? I mean usually when I play like this i play Kill Secure 
with T-Lords and 
while building 
but I have garbage CS! I don't take the minions! Those kills I got were totally accidental! Does that count as trolling?
Outside of this if you're jungling and the guy is jacking your CS just do what i do, in a non draft format autofill at champ select and don't force a preferred role because you make them want to troll you. When i started doing this i noticed that i won more games than lost because there was less stupid int trolling going around. Who woulda thunk it! Seriously in blind i've played some weird things in the support/top/mid/adc roles. its generally not too serious.
If you REALLY need to test a strategy run up a few bot matches. It's not that hard to get the gist of how a champion works with a build in there. Plus there really isn't much role fighting because if you get two junglers each one just takes a half of the jungle (divided down mid lane) Its not like the laners should get smashed in a 2v1 really, especially when you can gank w/e side you're on to assist them and get kills.
Otherwise play draft and pray the auto fill gods love you getting your role, it's not that serious
