yeah but (and i am not completly sure how this works, so if i am wrong, tell me) if they had access to world guard for protections, that means they could add themselves to other peoples protections, or even big protections like cities or spawn. and honestly, if they really wanted to... anybody could just get on the server for a while, be as helpful as possible, get the rank and start going to town on other peoples builds.
but i will stop preaching and just say, that is not a good idea...