I like this idea. How many people have to agree with a idea that is implementable for it to be added?
/region tempaddmember <town> <username> <time> would probably work. I'll run it by the dev for WorldGuard and see what they think about it.
This is a neat idea! Like previously mentioned, it could help with job assigning so players can't grief when you have to log off. I think it would be great for hourly, etc. perms on farms too. +1
I think it would be great! It would be so useful for things like renting out a farm for an hour and such +1!
I've submitted it here: http://youtrack.sk89q.com/issue/WORLDGUARD-2440 Most likely will not happen unless we get a customized version by a developer.