Pirate Galaxy.
I think that's what it was called. I got some good memories, lots of bad ones... in hindsight it wasn't' that great of a game... but it did do the whole PvP in a mostly PvE environment right.
It wouldn't take much to implement it here so we can get the best of all of it.
The concept was a simple PvE/PvP toggle with certain "Free-Fire" zones.
You had relative safety in PvE, but it gave an incentive to play in PvP - with a catch. If you toggled PvP on you were stuck in that until some other player killed you.
Otherwise the only dangers were the "Free-Fire" zones where it treated it as a PvP area, but you knew that going into it usually.
That should be relative easy to put in, make it so you can't damage PvE ships with the toggle. Maybe prevent interdictions as well?
As for the incentive? How about remove the rebuy cost to encourage players to do PvP - with no rebuy I would wager lots more would want to try it. That leaves the only loss being cargo at worst.
The "Free-Fire" zones should be areas like Combat Zones, where pledging a side of a conflict meant you accept another player could pledge the other and face you.
If that was in, I would think most of the issues would go away. The major consequence of PvP and griefing in general being that rebuy being taken away would ease it and those that don't want to bother could just lurk around in PvE mode.