It's something the restaurant has to request. It's sort of a loan from the Rewards Network to the restaurant, where they take the payments back as people in the network dine there. I always look at a restaurant that joins as one that is possibly heading into financial trouble if they need to go that route to borrow money.

While I'm not 100% sure, I think there may be just a marketing deal now too, where there is no "loan" just promotioins and the rest on the network.

Either way it costs the restaurant money, so unless they need the business they probably won't be interested.

If you know of a restaurant interested, they can go to reachdiners.com for information on how to apply.