Not always; Marriott does the same thing with some of their properties, at least in Hawaii! I'm currently holding a reward reservation with the following cancellation terms:

"You may cancel your reservation for no charge until xx/xx/2017 (21 day[s] before arrival).

Please note that we will assess a fee if you must cancel after this deadline.

If you have made a prepayment, we will retain all or part of your prepayment. If not, we will charge your credit card.

This fee equals 2 nights of your room charge plus tax for the first and last nights of your reservation)."

I didn't make a prepayment, so who knows what we'd be charged if we have to cancel.