I would just take the power...and don't bother using it. We had one guy last year who was getting romped on and sent an email to everyone saying 'I will trade my whole team, make me offers and I will take the best offer at each position, guaranteed'.
It sounded kind of fishy and the guy who got the most of his guys appeared to have gotten a boost from it but neither he nor 'Osama' contended after that and the other guys helped some of the other teams too. The team that won though didn't get ANYBODY from that. It didn't really matter in the big scheme of things.
I don't think that, unless people are colluding or something, there's any reason to veto trades. While there are a couple people who are less involved in the fiendish trashtalking, the smack is a MAJOR, secondary goal for just about everybody and there's too much at risk THERE , on top of their $10, to do anything really underhanded or collusory (???) w/ our group. We all work together and knew each other beforehand anyway.