I don't know what to think about restaurant.com coupons so I did a little digging and found out they use some shady practices when it comes to keeping restaurants on their list of eligible/available locations.
Accordng to this news report [oregonlive.com]
they hold the restaurants hostage in a similar manner that yelp does with their "preferred reviews", demand a minimum of 90 days written notice to withdraw membership as well as issuing coupons that were not agreed upon beforehand by participating restaurants. Not surprising from a company based out of Chicago.
Your best bet is to call each restaurant ahead of time and ask them if they accept these coupons because the restaurant listed could be in the process of having themselves removed from this list.