Slightly off topic, but I personally hate loyalty cards, though I use them because it's the only way to get the lower prices. I think places, like supermarkets, should just lower their prices for everyone instead of making you use a stupid loyalty card that tracks everything you do. <img src="http://www.traveltalkonline.com/forums/images/graemlins/duh.gif" alt="" />

As far as 'secret' discounts go, I won't sign up for something unless I know exactly what benefits I'm getting. But that's just me.