Steven,
Don't let my buddy Dean scare you off. He and I often act as DIS curmudgeons, pointing out some of the risks involved with some aspects of things.
Dean - as usual - is right that the renter of points controls the reservation. Therefore any changes, etc. have to be done through the renter. And they could take your name off the reservation, but they won't.
Why not? Because you would be screaming to anyone who would listen and that would kill any future rentals from that renter. Hundreds, probably thousands of people rent points every year without any problems.
The biggest risk, to both the renter and the tenant, occurs when the tenant has an unexpected change in plans. That could put the renter in the position where they could completely lose those points -- which obviously would mean that you would be the one to suffer. If you plans are subject to change, renting is not for you. Do a cash reservation and pay the price.
Even if you think there is no possiblity of a change happening, you need to understand what the renter's policy is in that eventuality.
Worst case scenario - you have to cancel and nothing can be done with the points. You are stuck. You are out the money you paid for the points. What do you do? You talk to the renter about allowing you to sell the reservation -- effectively sub-letting the rental. You advertise it on the rent/trade board and hopefully find a buyer.
You will need the renter's help in that case, and you will probably get it. No renter wants to see you suffer a loss. They want you back next year, and the next, and the next. So they will work with you...within reason.
90% of the time, none of these problems come up. You rent points, the renter makes the reservation, and you go to Disney. You have a great time, at a great bargain, and the renter is also happy.