How about having you or a geocaching "volunteer" have the edit/delete rights. A restaurant has to request the change from you and the change is reviewed for fairness.

Brian Cluff <brian@snaptek.com> wrote:

 I need
to think of a system for people to make reviews(logs) on the resteraunt
without the resteraunt owners being able to delete negative logs just to
make themselves look better. I really hope I can think of something
that will allow editing and fairness...