While it might not have said it when booking through Marriott, it sure does say it when booking directly through the Cosmo website (last item below):

RESORT FEE
Guests will be subject to a nightly resort fee of $25 per room plus applicable taxes. $25 nightly resort fee includes standard high speed internet access* (excluding select meeting spaces), unlimited local toll-free and domestic long distance calls (50 states), 24 hour fitness center access and tennis court access (based on availability). The resort fee policy for packages and promotions may vary.

*While the standard internet service included in the resort fee is ideal for emailing and social networking, for an enhanced experience, guests may upgrade their internet bandwidth to premium internet service for an additional nightly cost. Premium internet service allows guests to stream large media files, watch movies and game.

DEPOSIT POLICY
A deposit of the first night room and tax will be charged at the time of booking. The deposit policy for packages and promotions may vary.

INCIDENTALS POLICY
A valid credit card authorized to cover additional room and tax, plus $150 a night for incidentals must be presented upon check-in.

CANCELLATION POLICY
Cancellation of reservations must occur at least 72 hours prior to arrival date to avoid being charged a penalty of the first night of room and tax. The cancellation policy for packages and promotions may vary.

SMOKE-FREE POLICY
Smoking is not permitted in guest rooms or meeting spaces. The gaming areas and bars are the only designated locations where smoking is permitted.

CHECK-IN POLICY
Guest must be at least 21 years of age for check-in.