It's usually the sign of a troll, which more often than not will feed during the game. There should be something done if they repeatedly do that in champ select.
As for the accidental ban, maybe put a warning sign if the player wants to ban a team mate champ, or make it unavailable to begin with. I should not be forced to dodge and be penalized when this happens.
times where it could be "acceptable" to ban someone's champ on your own team
Its like when someone wants to play sona... (Before her hotfix) but they are last pick.. and no one else owns sona , and you know if you dont ban her 100% the other team is going to pick her, now would I rather deal with a op sona... or a bitchy team mate all game that I can mute. Imma chose the bitchy team mate.
I do not agree with penalizing, but I like the idea of the indicator. This would stop people from accidentally banning a teammate's champion and saying "I wasn't looking at champ select." Perhaps have some kind of marking on the champ-select tiles during banning phase.
I agree. If my team bans my chosen main who I have a great win rate and have played a lot of games on decides to toll me / my main then as far as I am concerned I should be able to dodge and not pay the fine. I was first pick on my team and my team mates say something like oops sorry didn't want to take the chance. Bs foul play is amuck.
The indicator sounds nice.
I like the current system. When someone goes Nidalee mid I want the option of banning that.
38% winrate stuff should be done among like minded friends.
Below Plat, there's no reason to ever ban an allied champion.
Why?
Below Plat, "power picks" don't matter. There's an entirely different meta, and a lot more things are open to play. Where there might be 3-8 viable picks in a position in the pro circuit (say, junglers, there's 
), there's probably ~20 below Plat (people jungle all sorts of things like Master Yi, Shyvana, Sion, Rammus, Graves, Fiddles, and many more).
You also have no idea what a person's champion pool looks like. In the pros, most players have an idea of the style of champion other pros pick. That's why Froggen gets hit with Anivia bans every game. It's possible to ban someone out and take out up to four (or more, depending on if the picks can be flexed) of their champions, which for some players forces them on to something out of the meta.
That can't happen in solo queue, especially under Plat. Most bans are targeted towards the champions with "toxic gameplay patterns" -- namely assassins and hook supports. There's 1-2 players in pros who have played Fizz (I know Ray's played it, but I think I've seen it elsewhere). But Fizz has a toxic gameplay pattern, so he's commonly banned below Plat. The same is true of Leblanc, Blitzcrank, Thresh, Zed, Akali, Ekko, etc., again, namely assassins and hook supports.
Since there's no power picks, limited trading (not everyone has every champ), and no ability to ban someone out, there's no reason to ban a champion your ally is showing.
Oh, and if you try to ban my champion? I have thousands of games played in my career since Season 1. I can absolutely suicide rush every respawn in one game and nothing will ever happen to me because it's not a pattern.
Like I said, 'repeated' offense. Yes we all ban troll picks now and then, but ints and trolls will do it on a regular basis.
And if the hint\warning is ok, should I make a separate thread so that alone actually gets upvoted? :D
Banning a team-mate's pick is just bologna. And its a great way to turn a player toxic or tilted right from the start. Myself included.
