I'm required to notify the landlord if anything looks amiss (such as moisture, mold, or bedbugs).The brainteaser question is what happens if the landlord legitimately enters the premises because of a maintenance emergency (or otherwise valid reason) and happens to notice something that violates the lease?

Go under the house and see if it's moist or wet.Do you have an exhaust fan to expel the moisture?

Even if a person is a slob, a mouse has to be able to penetrate the structure first (unless the tenants let them loose). 

They should do their due diligence in identifying current or potential moisture issues and advise on re-occupancy timing for the tenant. 

The moisture around the toilet made the glue unstick and peel up.

This will force away ground moisture to pump bucket and out of the house.How wet is it?

On top of that I would do a termicide soak application, then a layer of moisture barrier. 

You will get burned out motors.The tenant will have higher utility costs.That air flow and air quality will be affected.The tenants could claim the unit was not working properly making you eat the cost of a service call.They could also complain of moisture problems because the property wasn't breathing properly with air circulation.Filters are cheap and repairs are expensive.I definitely would not leave it up to the tenants.

You could also have moisture ants or other.

I originally wanted the same in the kitchen, but was warned against it at the time due to possibly moisture issues with tenants doing this or that in the kitchen.