Other tangible ways to gain info is to check the status of there EBAY accounts(assuming they have one). You could even arrange it to put the points for rent on EBAY with a buy it now, then pay through Paypal. Not perfect, but might give you even more piece of mind.
You might also get a written contract signed as well to help protect yourself.
There are also escrow services that can be used(money isn't sent to the owner until after the reservation date is used), if you are spending $2000 or more, I'd consider it.