I have had this happen. Five brand new towels . Turns out the guest was chaperoning teens . One got sick as usedcthe towels to clean up the vomit. Threw them away but didn’t tell me. I had been paid $650 for their stay so I wrote off the cost which was $25 to replace them (on sale at Costco). I have also had three instances where idiots used my blue and white dish towels to clean floors and tools. Couldn’t remove the stains. Tons of dark towels, paper towels and shop towels available but NO! They grab the pretty white ones. Sigh.
i didn’t charge. Or the person who stayed a week and tried to start laundry to be helpful and washed my white towels with something red.
Still - hotels DO charge for missing towels and hosts who are renting small spaces at a reasonable market rate price can’t afford to buy towels after every theft. That could be as much as 10% of their nightly rate.
I would assume it was a mistake and inquire to give the guest a chance to return them. Otherwise change listing to say missing towels will be billed at $10 each to compensate for time, gas and cost to get a new one.