I've never had this happen personally but I wonder if you can consider this a reasonable accommodation through ADA.  

I believe in general the numbers work best for rentals in Canyon county vs Ada county.

Hello everyone, a few months ago I asked BP members to advise if a kitchen pantry would increase the value of a house or if we should even ad a pantry and I got a "yes" from a few people on BP, I also needed to know if we should ad a glass shower door to master bathroom or use that money to epoxy the garage floors, I got yeses and no's on that question, so we risked it and did not ad a glass shower door ( you will see pic below of bathroom) and we did not epoxy the garage floors, we instead painted the garage. 

I too read the ad as more flowers than weeds.  

Ada and Canyon County are all growing.  

Service dogs are protected by ADA and meet very specific guidelines, and there are only certain questions you are legally allowed to ask about the dog.

Not a lawyer, no idea.A question I'd have in your shoes is "if I advertise the ramp, am I implying that the entire property is ADA Compliant, and could I get in trouble if it wasn't?"

It has an ADA bathroom.

A couple of considerations:1) Can you make it ADA compliant?

Below is some references for your use.Fair Housing rights are controlled by the Fair Housing Act, the ADA (see above) and Section 504 of the Rehabilitation Act of 1973, with a few provisions in the Architectural Barriers Act.