Marriott writers do not write well. They will eventually be sued because the policies written are not what they meant to write or are intentionally misleading. For example, on a regular rate, the cancelation policy states the following for a reservation beginning on September 18, 2015
I believe they are EXCELLENT writers (for the corporation's benefit) for this exact purpose.
How hard would it be to write "you may cancel up until 11:59 PM hotel time the day before check-in" ? This is way we understand it here after great debate and verification.
So 95% of the populace see the vague terms and figure "I better make a extraordinary effort" to get there and use it or blame themselves if the penalty is imposed...