Terms and Conditions of Membership say...

Hotel Awards

1. Preferred Award Nights can be redeemed at the time of reservation by contacting the Account Service Center or through the Internet utilizing the Preferred Guest member's personal identification number...

Nothing there about doing it as a walk-in to the hotel. Also, not advisable to try it this way.

Sincerely,


William R. Sanders
Customer Service Coordinator
Starwood Preferred Services

[email protected]