I also have rented numerous times - mostly from the same DVC owner. We have a trusting relationship so I do not fear not having a reservation when I show up! Of course, you never(well, only once in all my DIS time)have heard about someone getting cheated. You could check out the DVC rental board and get a feel for what people are asking per point. $10 is still a good deal that can be had. You can always ask for references from the renter, if that would make you feel more comfortable. You might want to check to see if the renter is new to DIS(see the # of their posts)to determine if they've been around on the DIS a while.
I LOVE, LOVE, LOVE my time at the Boardwalk Villas - I'll never convince my hubby to buy into DVC, but I can spend my 5 nights a year there anyways for about what I'd pay at a value resort. Trust is a huge part of doing this, but I've never had anything but helpful DVC'ers that I've rented from.