Nothing can be done because its not against the rules to play off-meta champs and summs. Although I've had my fair share of troll picks in ranks, like support J4 with ignite flash, I have to admit I've had cheese picks come out on top in the past.
It really comes down to one thing: Is the player legit trolling, or is he actually very proficient with that specific setup.
People complained a while ago when some people experimented Vayne in the jungle, but my personal experience tells me its not all that bad if the player actually knows what he is doing. You should trust the troll sometimes.
Except Support Nidalee. Always report Support Nidalee.