It's a good idea in principal and I think it should be done.
My only concern is that it might be abused/misunderstood in the sense that the reason might sound too 'official'. If the game asks you "Kick Failer for teamkilling?" Then everyone is going to vote 'yes', even if the teamkilling is not proven. After all, it might just be the description someone who doesn't like Failer put into the poll.