Taking
@Screemonster 's proposal for a PvP-flag that would disable the ability for an attacker to destroy a ship duly flagged - then running with it - I propose the following to further the discussion:
That a flag indicating ones preference for PvP is implemented (preference only, it doesn't stop PvP);
1) If flagged for PvP:
a) the player loses the ability to use menu exit while undocked and instanced with another player;
b) tracking "lost connection" count and frequency while in-danger due to player combat and instanced with players with a view to inflicting the player with a rebuy if the lost connection count exceeds a threshold in a time period;
c) possible change to the block feature to only block communications for players that the player has blocked. Would not affect blocks by other players themselves flagged;
2) If not flagged for PvP:
a) the player's ship can still be interdicted and attacked, but not destroyed, by another player;
b) the player loses the ability to interdict other players (to stop "annoyance interdictions" of players by unflagged players who can't be destroyed);.
The flag status of each player could be displayed on the HUD scanner using a hollow marker other than square or triangle or possibly by placing a dot in the centre of the hollow marker.
The Wing feature would reasonably be changed to only permit wing members with the same flag setting with auto-booting for players who change their flag while winged.
Changing flag state would reasonably require the player to log out of the game entirely.