Errm… how is that any different at all than our current situation? You already can’t leave matches, because you get banned. So the tank in this scenario isn’t going to quit. You still can’t force them to participate. So they still end up just “throwing” to make the match end quickly.
The end result is exactly the same whether your scenario plays out or not. The only difference is, with a “Surrender Vote” option, you at least have the chance, as a team, to say “Yeah this isn’t working, let’s just move on to a new lobby.” where everyone can be happier.