This depends...For example, if the house is a short sale, it could be in either pending or back up status situation. Sometimes, the status changes after the inspection is done.
In back up status, the house can be shown, but no other contracts should be signed.
I've seen regular sales being shown and in back up status more often, recently.
In the end of the day, you are the homeowner, and nothing should be done without your agreement to it.
Best of luck,
Beachfront Realty, Inc.