If I jump in a tank that is occupied, I'll use the MG position only, to clear infantry and also to point out targets for the main gun ( while using the tank comms keys to alert the driver/gunner to the threat ), apart from that I'll wait for my own tank.
I have no problem with team tanking, provided I'm using comms and the other guy is, otherwise it is frustrating to line up a shot in a perfectly angled tank just to miss as the driver decides he saw a nice butterfly on yonder hill...
Having 3 guys per tank suits me if it is the enemy too, I get to kill 3 of them with one shot
I don't agree with locking tanks, but I do wish people who chose tank classes would wait for their own tank or teamtank with people who have requested such.
Nothing like waiting at spawn when everybody drives off, gets killed, respawns then they demand to get in the tank you waited for, only for them to start MGing and popping off main gun ammo on the way out of spawn, aimed at nothing and just annoying the hell out of the team.
The guys who use the TT prefix in their names are making it clear that they want to teamtank, the others ( like me ) would prefer not to have anyone else in the tank.
Easy system if you ask me
