I'd love to see this implemented as a config option for more vanilla-style servers without subjecting your players to the fear of losing everything while they're offline.

"onlyWhenOffline": <delay in ticks before activating>
"onlyWhenOffline": 12000 Example
"onlyWhenOffline": -1 Default setting

It changes all of an individual players claims global permissions to true while they are online, and reverts to normal after they've been logged out for a while.