Like social security or disability.  

You can not charge a pet deposit or pet fee for a legitimate service animal or assistance animal for a person with a qualified disability.

Just don't violate ADA on this one. ..don't ask what her disability is, etc.  

Do you count social security and disability as income to calculate 3X gross of the rent?

It's not super relevant to REI or BP members because the intended user of the product isn't REI, but it is one of my favorite things out there.Also works for parents providing housing for adult children with a disability.

We also made a reasonable accommodation for a tenant with a qualified disability to allow their service animal.

We already pay enough people not to work;  some days I get the feeling there's only about a dozen folks in this country that aren't receiving some type of "disability" for something.I once had an applicant ASK me at the showing if I do the cash for keys deal. 

Also, you cannot garnish wages from people on disability.

In broad generalities, those who have steady low income jobs or quiet folks on retirement or disability seem to be the most attractive, consistent, and best tenants.

There are many tenants who try to get around pet policies by claiming to have a disability or claiming their pet is a service animal.