They may have health issues and want to minimize disturbances.

Also states: do not disturb occupant.

Stay out of it....Tell the other tenant that if there is a disturbance they are concerned with, then call the police and let you know the outcome.Unless this becomes a very regular issue...with multiple police calls..... where they are violating the lease in regard to infringing on the other tenants right to peace and quiet....I wouldn't even contact the fighting tenants.Do not become the outlet for a tenant to call you for every petty issue

Old tile glued to floors with asbestos mastic is not a problem unless disturbed.

Disturbing asbestos shingles is the issue not having them. 

There is also the need for them to access the area for maintenance at any time without accessing the building and disturbing the residents which this setup helps accomplish.

I’m helping homeowners without disturbing the market that typical home buyers are looking around at.

Kudos to the other posters for researching your market value for you too.I might try saying less in the ad about how you intend to nickle and dime the renter, sometimes less is more.That said, having showings and no applicants is disturbing.

I have come in contact with seriously disturbed people that get PISSED off when you can't make an offer that works for them.You really do not want those people to know where you live right?

Too many licenses will disturb the local system, that is mainly how they think.I agree with @Mike Lambert that Spain in general is a year round option for tourists because outside of summer (which honestly sometimes becomes a bit too hot) the sun shines even in winter times with very comfortable temperatures.