Foursquare for Loyalty Programs

Hitting nearly a million check-ins per day, location-based social network Foursquare's success is moving beyond speculation and into the realm of reality. Many companies are beginning to - effectively - market themselves using the service and offering deals based on where customers are checking in. Pepsi is one of the first major brands to capitalize on this, using the service to help users locate the nearest Pepsi vendor. 
How does this affect your loyalty program?
We've already discussed how mobile devices are going to be the next new loyalty card. Many companies have already utilized the "Specials Nearby" feature on Foursquare, which allows users to view sponsored messages by companies near where they've recently checked in. Foursquare already has a points-based system into their program where users earn points for their number of check-ins, first time visits etc.
What if companies utilized those same systems?
Could companies reward their customers for check-ins? Many loyalty programs are based on points or engaging in some sort of action a certain number of times (usually actions that result in points rewarded). Customers would earn their normal Foursquare points and could earn discounts or free items as a result of redeeming those point totals. 
Starbucks has already instituted a similar system. They've recently developed a program that allows Mayor's of their various locations to be eligile for dollar off discounts for drinks. This not only rewards loyal customers but ensues a competitive like spirit among visitors. Frequent Starbuckers won't be checking-in more just for that dollar off - but for that title of "Mayor" too. This system of loyalty turns Starbucks' loyalty program into a game and makes it a much more interactive experience incorporating social networking channels.
What other ways do you see Foursquare or like services being integrated with existing loyalty programs?