One way to check if a Hyatt is participating in the 48 hr sale is by clicking the hotel link. Once at the hotel main page, click on Special Offers on the left hand side link.
Example:
http://montreal.hyatt.com/hyatt/hote...uestid=1159380
HR Montreal
Save 15% off room rates. Hurry, offer ends midnight July 25!
Reserve By: 25 Jul 2012
Stay: 08 Aug 2012 - 04 Nov 2012