Riot Please listen to this blind pick idea

So i notice alot of arguments that happen in the lobby are over lanes and usually when a person loads in they might not load in at the time the lane is called and might miss the lane being called which seems to have caused arguments like "i called it." No you did not!" This is a big issue for the players who actually want to have fun. I believe that the chat should be locked until the 5th person is loaded into the lobby and is able to see chat.