I just thought of something: Is your air bnb located near a large hospital or medical center? Perhaps your guests are prepping for colonoscopies. A lot of people stay in a hotel next to the hospital the night before so that they don't have a long car ride with extra strong laxatives on board. Pro tip: bring your own extra soft TP if you plan to do this, the hotel stuff is rough.
Is this a lead in for more toilet humor?
To answer your question, no. I live near a big university and people come for football games. Hotels get booked for an hour drive away, so Airbnb becomes very lucrative at particular times of the year.
edited to add--- to answer other people's questions of possible TP usage---
1) The bathroom looks clean when they leave, so its possible someone is wiping down the sink, toilet, etc with toilet paper. Two days isn't much time for a bathroom to get very dirty though. The guests have been very clean in general.
2) No dietary or medical concerns to report. I cook them breakfast, ask if they have any restrictions, and they're vibrant people in general.
3) Menstruation is possible, visitors were about 1/2 male + 1/2 female, but in contradiction to what others might think of me, I don't remember what else was in the garbage can besides the toilet paper tube.
4) TP for blowing nose, makeup, etc, is likely. We don't have any kleenex set out, though I don't remember anyone with a runny nose. That needs to go on the to-do list, along with small trash cans in the bedrooms. Just isn't something that occurred to us.