I would suggest we can employ football match system into it. Instead of a single 6 point deduction (very hard punishment) we should develop milder one.

6 mark deduction misbehaviour
a. Dopplenger appears in same/opposite team (same person's control 2 or more plane in a single match)

3 mark deduction misbehaviour
a. Radio interaction (inter communication between teammate or enemy)

1 mark deduction misbehaviour
a. writing foul language, saying bad words in the forum area

Leaving field early will be counted as 0.5 kill, so no need for this misbehaviour punishment, if they think its worth they will do so.

Just my 0.02 rmb cent

P.