I have to second the point that this is a lousy program. In addition to what is mentioned above there is no way to rent for more than one week. Adding insult to this is the fact that you have to wait 24 hours between free rentals so there is no back to back option.

I was looking to use my 27000 points for a free two week rental for a nice driving trip. Was told the max is one week. Then asked to do one week one way. Was told fine, but I'd have to wait 24 hours before I could begin my return. What a joke...