PSA banning intended champ picks
Even if that person hasnt played the champ much or you think the champ is fucking bad or whatever the reason may be, don't ban champs people intend to play.
And don't cry on the forums about how the player, now frustrated/angry at you for being a total asshole expecting him to play what you want him to play, decided to troll his ass into next Tuesday, making your ranked experience miserable.
No one cares if you are in promos, no one cares if you think that champ is a troll, and no one cares if you try to coerce others into taking picks you want them to pick. If it really were so bad that someone picked a champ you didnt want them to pick for whatever reason, dodge the game and accept whatever loss and recognize that at least you didnt waste 40+ minutes.
TL;DR banning a champion someone intends to pick for whatever reason is probably going to frustrate them and give them the incentive to flip you off somehow, be it in-game trolling or something else.
EDITOR'S NOTE
Sigh... For those who don't understand, the spirit behind this OP isn't about whether it's right or wrong for people to react the way they sometimes do when their intended pick is banned. It's simply to point out that some will react very negatively in the first place and you shouldn't be surprised or upset at what can be seen as a natural reaction. This thread is mainly in response to another thread that has gained traction recently within the boards where the OP complained about having a troll support on his team after the OP banned the troll's intended pick (the troll then made it clear that after the OP was being a dick he was going to troll).