I have rented points out to others, as well as rented them myself. If you are short a few points on a ressie, it makes good sense to rent from another member. My experiences are mostly positive. There are some negatives to renting out to others--
1. 20 million emails from people, and most are just kind of interested to see if there are any vacancies at a particular resort, but don't want to rent from you, they just want you to check, like your were CRO, or something.
2. People who rent and then back out, leaving you with points that you told others was sold out.
3. Cancellations less than 31 days before arrival, leaving your pts in holding.
4. People who sound like you have a deal, then try to renegotiate at the last minute.
5. People who agree, you make the ressies, then they disappear.
6. People who haven't done their research, so they don't know that weekends and weekdays have different amounts of points, and they think you are trying to scam them.
But a big positive--you make lots of new friends, and those people will return next year to rent from you!