Our neighbors were selling their house, went on vacation, and we couldn’t figure out why lights were on all night...so we texted them...they got listing realtor in...someone had turned every light on AND disconnected a water line in kitchen, which caused flooding...cost them a lot to fix. ALWAYS be there (or close) when house is being shown.
We either sat in the back yard or went to the barn in inclement weather but made it clear we were still there.
Risk management is a product of consequence and probability. How many people are trustworthy or competent and how much can they screw up?
We also would not allow showings when we were out of town.