In my opinion, Lone Fighters (LF) mode as of now does not provide sufficient punishment for tk and does even less to discourage griefing. Sure, a misplaced bomb can send the pilot right back to main menu, but so far, nothing can prevent a player from going after the same teammate, killing him again and again for, say, one time less than the autokick limit ( however many that is ) and go on to finish the game
This can be reallly frustrating for the victim, but because it’s not cheating, I don’t think the griefer will get any punishment other than reduced xp income 
Many other games have implemented the following mechanisms to discourage tk and / or griefing and I strongly suggest implememting at least some of them:
- “forgive” option for the victim (which is usually required for the rest of mechanisms),
- respawn points given back if the tk’er is forgiven,
- added waiting time to spawn for the tk’er (scaleing up with tk numbers) if not forgiven
- nametag highlited when certain team damage threshold exceeded (wink wink pink bote)
- team damge reflected on self upong gaining the highlighted name tag (victim receives no damage)
Feel free to add more ideas to this list.