Hi Rroo,
Which site are you booking them from? Some sites (orlandovillas, onlinefloridavillas, villasflorida, disneypremiervillas, for example) require the owners to verify they own the villa listed every 6 months with a current utility bill. For added peace of mind you could ask for the contact details for the owner's Management Company, and check with them. I have done this for guests on occasion when asked.
Finally, don't be afraid to ask the owner any questions to put your mind at rest, most owners are more than happy to talk about their pride and joy!!