Renting out your home on a service like Airbnb is supposed to be good for your bottom line, but it's now clear that it can create some headaches if you're a homeowner. The Wall Street Journal is warning that banks may turn down your attempt to refinance your mortgage if they learn that you've rented your home on Airbnb. Simply speaking, banks tend to see homes as either personal residences or investments and don't like the risk associated with the latter. While some banks may allow a gray area between the two, others won't be so kind -- Bank of America, for example, won't give you a home equity line of credit if there's a "material amount" of commerce in your home.