An interesting inquiry. First, I think the answer may be different for a deeded week (the old program) versus a week acquired through use of Vacation Club Points (VCP's). The issue is that the cost to the lessor "for the same vacation" using VCP's is much more expensive than using a deeded week (if you have one). This is illustrated by the abundance of week vacations on Redweek but very few 5 day reservations (acquired using points). So, those offering weeks for rent are most likely renting out deeded weeks. The weeks are exactly the same in use.
Please don't buy VCP's with the idea of acquiring reservations to rent out - it's insane.
Den