Keys mechanics.

[rigeborod]

As there's now p2p hats which vanish if someone try to take it after killing player, I assume this mechanics could be reused.

Idea: slave keys should allow to fully use gates (from both sides) but after they're linked to the character they vanish on his/her death. Obviously all this difference between master and slave keys is in the game to make it safe to travel with keys. And achieving it without any inconvenience is a good thing, IMHO.