Pssst..premades do not preclude you getting killed by friendly fire, even with people who actively try to NOT fire on friendlies, it will happen. Just ask any military force for the entirety of human history
Fire control is a very hard skill to find, most people see the enemy and just start firing and do not stop until said enemy is dead. They pay no attention to what is between them and the target usually, which leads to a lot of friendly fire incidents. And there is also the player who pays no attention to who ELSE is firing on the target they have, and they will run into someone else's field of fire and then complain about getting shot by a friendly.
These are things no one has any control over, PGI could put in penalties for firing on friendlies, beyond the current totally pointless TK penalty, but it would not change anything. I TKed 2 times in the past 2 days. The first time I TKed with Streaks, put a set of 2 of them into the back of a teammate who simply happened to step into the flight path at the wrong time, wasn't there when I fired them. Second time I TKed someone with my lasers AFTER the target I was firing on died and the lasers kept firing and hit a teammate on the other side of the enemy who was no longer there..right in the face. Both cases were totally accidental and both were totally beyond my control, and they will both undoubtedly happen again..and again.