Did you ever think about rewrititing this so that it works like that?

Every player has a protection no matter if he hits anybody.
Hits will just not do any damage as long the attacking player has protection.
I've seen turning off damage to other players in Clan plugins e.g.
So, there should be a way to make this happen.

This would make time punishment for attacking players with protection obsolete.
Also, and more important, a protected player could never abuse his protection to attack other players.