I think guests are extremely curious--many like staying in a private home for authenticity and the chance to explore another person's life--and most open every drawer and try to open even the locked doors/cabinets.
We are now at the point where we leave "easter eggs" out (a whole drawer full of high end makeup and toiletries I don't use anymore, a bottle of vodka in freezer etc.) to hopefully keep guests from getting more aggressive. Believe, the makeup gets used, the toiletries get sampled, the perfume and vodka slowly and steadily disappears from the bottle...
If you lock a door, put the lock up at eye level. I used to put the hasps at bottom of door to be more aesthetically pleasing but I'm sad to say that so many people tried to open it (despite large "PRIVATE" sign) that the hasp dug a chunk out of the wood.
DO NOT ASSUME YOU WILL FIND DAMAGE OR THEFT IN TIME TO KNOW WHO DID IT!
1. Passport stolen from its case (this was the WORST)
2. Boxes in attic (including one of family photos--why?) had been opened, rifled through, and photos left all over attic
3. Glasses with local brewery insignia
4. Towels, books, (these are a cost of doing business, I don't care so much)
5. Expensive condiments (coconut aminos, maple syrup)
6. I used to have a bottle of vodka in my freezer. I haven't had a sip since May, but every couple of weeks, the bottle is down an inch or so. We consider this another easter egg...
7. Midcentury vase was broken, glued back together and turned so that damage wasn't visible until time to dust
8. Fancy smelly candle