If you go to their website, you will find there's a lot of "fine" print associated with those loyalty cards. For instance, to receive the $15 visit reward, you have to go to one of the restaurants 20 times in in month. The month (and visit frequency) starts over at the first of every month. So, you would have to visit one of the 5 locations 5 times per week, roughly. Two visits to the same restaurant on the same doesn't count...has to be two different locations.
Here are the FAQ's for the cards:
Loyal Tee Rewards