The best cav are always a bit careless when it comes to teambumps but you honestly cant expect us to warn someone for accidental teambumping. There are people out there that will press M at any little accidental teamwound just to be a dick, to lol at their friend, or simply because they got hit and the big text came up. Come back when you have proof that he did it intentional and yes, I'll ban him on the spot. Until then enjoy the free multi that cav provide you when you get balanced on the cav superstar team, or rage at them every time they lance you.