How do I protect myself legally if showing someone's house?

If I’m showing houses while owners are away, how do I protect myself either from false claims against owners that something has been stolen, or in the event of actual theft by the interested buyers. Is there some sort of insurance policy I need?

Given how people in foreclosure need money, I could see how they might be tempted to pull something over, ie. claim $500 was missing of the nightstand, etc. And given the number of scam artists out there, I could see how a couple could pose as interested buyers just for the opportunity to steal as well.

Thanks.

Tell owners to lock up or remove valuables before the showing.

Pre-screen buyers and don’t let them wander through the property unattended.