I've had far too many trolls do this, it's really annoying in ranked.
When it's done by accident, I can understand, I've seen people genuinely do it by mistake. And then there are plenty of people who flat out admit that they're doing it just to grief.
Prevent them from banning out picks that have been soft-locked by teammates, problem fixed.
There are legitimate reasons to ban a teammate's pick intentionally, and this list doesn't even include all of them.
The champion is new or recently majorly updated and the player doesn't want him played in ranked.
The player is afraid the enemy team will pick the champion first.
The player simply does not want to play a game with that champion in it.
The ban mechanic is before the pick mechanic for a reason - it's considered higher priority. There's 100+ champions in the game - you can always play another champion, but if you don't ban a champion there's no guarantee it won't be in the game, and possibly on the enemy team. Hovering should ideally initiate conversation if someone was going to ban your champion, but they are by no means obligated to converse before doing so.
meh first pick should be safe but everything else is up for grabs.
No thanks. I don't care if my top laner is a Fiora/Jayce one trick, I'm still banning out those champs I dislike.
