I just realized that if I have a visitor's gate, there's no need to lock it at all - people who have permissions for the claim can open and close it at will from both sides, and those who don't will have to commit a crime just to open it, and then (I think) can't get in.
The only reason to key it is therefore to prevent anyone *else* from keying it.. which would be a crime, but would really mess us up since then they can effectively close the gate forever on us.
Allow the option to make a gate unkeyable at all.