Add a command that disables mob spawns for the specific claim you are in, for instance "/ClaimMobSpawning On/Off"
This would disable all spawning including spawners and mob farms.

This would be useful for builds so that torches or other light sources wouldn't have to be littered everywhere, making a build look less appealing. Or while building so that you don't have to constantly fight off mobs between every block placed or only building during daytime making the build take twice as long.

I believe having the command disable all spawning would help towards players using this solely for build claims, since dividing up your base into several claims to still have farms going would be tedious, so players would still have to fend off hostiles from their homes.

Alternatively, this could be a staff only command to make sure players don't overuse it and make the game much less difficult, certain parameters would be set in place that would disqualify a player from having mobs disabled in a claim, I.E. does this claim have farms? Or are there any other builds in this claim that help the player in progressing/surviving? Although these are just vague ideas to parameters I'm sure some could be set in place to insure quality of experience for the player.

Difficulty:
As I haven't done anything like this myself, I imagine this would be moderately difficult to do yourself, I do not know the plugins the server uses but maybe there's one out there that would work this way.

EDIT: This could also be made into a new custom Wilder block, that when placed disables spawning for a radius around it.