WFB is definitely NOT a standard across all Marriott/Ren properties. Based on my experience with Marriott/Ren properties, it seems to be as follows (this is conjecture to a certain degree):
-- Marriott owned/managed hotel - always offers WFB
-- Franchised hotel - may or may not offer WFB, franchisee's choice
My other observation is that in those properties that DON'T offer WFB, the cost is still 9.95/9.99. So in properties that do offer WFB, the LD component is essentially a freebie.
You would think that Marriott could make this part of the franchise deal; you have to offer WFB. WFB is something that adds to the overall brand consistency.
Just my two cents.