I too have rented points. I haven't taken the trip yet so I'll report back after I do (Jan). A fair price for points is $10.00each; you will see offers for less but usually this is when someone is really in a jam and it's short notice. $10.00 is a bargain.
But , I think everything will work out just fine. THe person I'm renting from had a history here on the Dis - when I saw her offer to sell points I checked her history of past posts (she seemed "normal" - talked about her family, faith, etc... and she had been here on the Dis for quite a while). Of course, this doesn't guarentee anything but I feel more comfortable with that than renting from someone with only 2 or 3 posts - no history to compare, etc...
Some people offer contracts (I hope she won't mind me saying , but Shontell Crawford is one of them - she is a real estate agent and has her own business in timeshare resales. You can do a search here on the Dis and email her to see if she has any points to rent. I would have rented from her if her home resort had of been the Boardwalk. Anyway, you can tell her Puffy2 recomended her). Others will offer references which is good too. In my rental case, the person I worked with sent me a receipt of sorts.
I also called DVC membership and was able to verify the reservation over the phone. I'll do this again prior to leaving for the vacation.
One last comment, if anyone ever is "stiffed" we certainly will hear about it here on the DIS!!! And, I've NEVER heard of anyone ever having a problem. Lets hope it stays that way because one bad experience could really ruin a good thing for everybody concerned.