Are you sure about that?  Pub 527 says, 

Used as a home and rented 15 days or more. If you use a dwelling unit as a home and rent it 15 days or more during the year, include all your rental income in your income. Because you used the dwelling unit for personal purposes, you must divide your expenses between the rental use and the personal use . . .

But the question here is whether there is profit motive.  Otherwise, the deductions would be miscellaneous on Schedule A, but not allowed until 2025.  In reality what is happening is that the owner is being reimbursed for part of her expenses for taxes, insurance, utilities, maintenance and repairs, so the payments are not taxable.  That argument might succeed with IRS or Tax Court, but it would be hard work.