I was just thinking today that password-protected rooms could be another solution. Easier to implement, I imagine. The only downside is you couldn't make new friends.
Another fun idea: Transporter pods to board enemy ships?
but lets say there is 1 public ship thats new and wants freinds, and 2 other freinds come, greif the ship, and they votekick the first guy? maaayyyybe guests cant votekick? There are some problems with that idea, buddy.