Or there's also oubliettes. They worked for the French.

[Not really, but hey, he was cool with shoving Peter in an asylum and leaving him there as opposed to most other things. Death didn't always seem to stick, in his experience.]

Just... let's wait until we get to Cothromach before we start talking about oaths and stuff. Maybe you can talk to Jon about what kinds you actually want people to say. Make amendments about fae intervention and things like that. It'd be a shame if someone went against their oaths to you because of the damn fairies and got punished for it.