gtahotels.com is indeed a voucher site - I've run into that with the old Wyndham BRG. See link and emphasis added below - note they say the reservation is guaranteed with
them, not the
hotel.
http://www.gtahotels.com/customercare/main.php
Instant Online Confirmation
Upon submitting the booking form, you will be given a confirmation number, as well as a link to an electronic voucher. You will also receive an e-mail showing your booking information. Your booking with us will then be confirmed and we will not change your accommodation or the rate – we guarantee it.