I believe the limit is 3 betrayals...once you betray anyone else after that you can be booted. They also carry over from previous games. So if you betrayed by accident in one game... then two pass and you get another. Then another in succeeding game you can be booted for anything after. Not sure when it "resets" but I've always found just dashboarding once the game is over resets it. But I can't be certain, I just know I've been booted once...and never ever again, (though I rarely betray).
I have no idea how exactly it works but it's not as simple as reaching a certain number in one game. It's probably a certain amount of team kills in a certain amount of time that makes it happen. Once you reach that limit every kill after that will give the option to boot you.
Yeah i hate when people wait in the beginning of the mission and you travel really far away and then you die and have to start all the way from the back unless they are moving and stopping then there needs to be a boot.
If tomorrow is yesterday and today is tomorrow then tomorrow is today. Gt: G4MECRUSHER101(all caps).