Investors & landlords

I am not taking childcare credit but i plan on paying my mother using my dependent care FSA - but i wanted to know if it's better for both her and I tax-wise to be my household employee (and watch the kids at my house) and take the nanny tax exception or to be in her house and report the income as "hobby" income (since she is not in it for making a business) which multiple other tax sites are suggesting is fine. Although the person above seems to suggest that is not the case.