I had a recent guest that really was looking for a home that had easy access for people with physical limitations, e.g. going up stairs, slipping on carpets. I think it would be great for Airbnb to include a check box for hosts to indicate that their home is can accomodate people with limited physical abilities. More detailed items could be ramps, no stairs, walk-in shower, handles/grips in showers/bathtubs, doors wide enough for wheelchairs to get through.
This way people can more easily search for places when traveling with people who have trouble with stairs and using bathrooms.