I ussually try to open communications with the other player when i'm a loki.
On some occasions I made an agreement not to sink the other player (should he end up losing). I've gotten quite a few compliments from players that weren't really wanting to fight me (another player) afterwards. I have even had one player who didn't want to use his reps (until he actually hadto to survive), because he knew he was fighting a loki. When ending up against an obvious new player, I sometimes only fire one gun instead of the whole broadside, or I push them in the wind (like a boarder would do) and then escape from the boarding and let them try again ... no point in murdering a new guy, is there?
But yeah, I don't get why anybody that uses a rune, would then try to run away in the battle ... Why did you even use the rune for in the first place? You know you will be in an inferior ship (makes no differene to me, I sail crap in open world all the time) and not likely or supposed to win. You also know that you won't get any xp or gold, so not playing as a loki can only be griefing?
I have had players that run away as soon as they see it's a loki they are fighting ... I hunt them down as long as i can then (easy to be denied as they only have to chain me once) ... one could say that the player is griefing the loki-player? People have ran away while they were full health and the ship I got was already down to half structure and only half a flank of armour on one side left ... all they had to do was fire one more broadside to make me immobile, but they choose to run away ... I'd say that is griefing ( 😉 ) I demand to get sunk in every battle!!!