Beyond the fact that it is against RCI's membership terms, there are other reasons RCI, II and the other exchange companies don't allow rental of exchanges. You don't own the property, and you don't have the permission of the owner of the property to rent it out.
This would be no different than leasing a summer home, and then subleasing it to someone else. When I deposit my weeks to RCI, I give them permission to use those weeks in any way they choose, but I do not give them permission to give you permission to sublet.
If you exchange into my property and damage it, you have signed a contract with RCI, and by extension with Me, to cover the cost of any repairs. If you rent that exchange out, your renter only has a contract with you (and perhaps with the resort when he places a security deposit on file when he checks in), not with RCI or with me. If something hapens to my property, are you prepared to face the liability? At least if RCI's renter causes problems, RCI has deep pockets.