Now that the horse is out of the barn, so to speak, perhaps the next time you have a contractor in your home and you can't be there, it might be wise to close and lock the doors to the room(s) that shouldn't be disturbed. Of course, if the work will be done in a room with some of your toys, then that's another issue.
For over 30 years, I lived in an area that was filled with potential for dishonest workers, so I never left anyone alone in my home.
However, here, the climate is waaaaaaay different. Believe it or not, many people still don't lock their doors when they go to the store, etc. But, this is a rare place.
I still have a hesitation to leaving someone on their own in my home, but I'm getting more trusting because of the integrity of the folks in my area. Although, I do continue to be at home when work is done, but I'm discreet about where I am while the workers are doing their jobs.