Ranked games

If we have a T.O.S that says its bannable to have bad connections then why dont we have a system in the game that does not allow people to join ranked if their ping is above the point of "Lag" because you're obviously not going to ban everyone but do something that wont affect our ranked games if someone is suddenly "lagging" or even if there is someone in a ranked game that is ALWAYS lagging but noone reports them for it and its ruining the fun of climbing rank and getting to higher places especially if the systems are telling us we are not suppose to be in this tier but cant move up because people think its a good idea to join a ranked match while they are having a horrible connection.