One of the common problem is sticked c4s on us. Enemy units, specially sbhs, put c4 on us but sometimes we don't notice it. It's ok but if we see c4 on our team member, we can't warn him without writing chat and sometimes he can't follow chat while he is fighting. So there should be an option to warn him with Q. Game should send him warning message about c4 when we use Q key to c4 on him/tank. Warning message can be like "follow me" message displaying center of screen or something else.