Last year it happened gradually from the time the new plan details were announced until close to the end of the year. I would say there were still some restaurants not on the brochure in November that ultimately signed on. I can't remember the exact timing, but I do know it was a few months after the 2008 brochure was first posted before it was final.
I'd say there's always a possibility some won't sign on, but the vast majority will.