Not in any sane medical system
I wouldn't argue that point. However, they're already doing it-- my major carrier employer healthcare plan for example, offers a discount if you buy a FitBit and meet certain goals with it. Goals that, according to some fellow employees who've attempted to meet them, are next to impossible to achieve. No one ever said it was going to be "sane."
FORTUNE'S FUN FACTS TO KNOW AND TELL: A firefly is not a fly, but a beetle.