This is to suggest that when a character guards an exit, the guarding gets switched off if he or she moves between rooms.
It's kind of ridiculous, for example, to start guarding an exit, then later walk around several rooms, talk, fight and eat, then upon coming back finding yourself blocking someone.
But what if I am actively chasing someone and trying to block them from turning right? I think it makes sense if you are trying to guard a direction.
Yes, it is ridiculous to keep guarding an exit, socialize, forget you are guarding, and accidentally block someone from moving.
But it's also possible to want to stop a chase.
How about adding a guard option for the prompt? If you are guarding a particular direction it will show 'guarding <direction>' to remind the player to stop guarding if he or she doesn't to be.