I feel safer renting my unit TO someone from TUG, and if I were to rent from someone, I would feel safer renting FROM a Tugger. It just feels like a smaller and safer community than ebay or Redweek. Maybe that's a false sense of security, though.
When I've rented out my week on TUG, I've tried to provide as much info and peace of mind to the renter as possible. Sometimes I am surprised at how trusting people are. (One person was a lawyer and asked for a copy of the deed, though. That was thorough!) I've rented points from someone on VPE and was a nervous wreck until I had those points in my account. The person renting them gave me all sorts of proof and documentation, too, but I was still scared of being scammed. Recently I rented out some points and the person didn't ask for anything, though I emailed them some screen shots showing my week was available and how many points it was worth. They were willing to just pay me and wait for the points to transfer.