The only place we had trouble with this, was last Sept at San Angel Inn. I didn't want to waste a TS there as I don't particularly like their food, so when we ordered we told the waiter that we would need seperate tickets and that my son and D-I-L would be using the dining plan while all I wanted was the cheese fundido using my DDE card. We were told that only one discount was allowed per table and either we all used the dining plan or none of us could. After arguing with him for a few minutes, I asked to speak to a manager who said the exact same thing. I asked her what if I had just met them there and didn't have the dining plan, would I still not be allowed to order the fundido. After thinking about it for a few minutes she finally nodded and said that was right, we all had to use the dining plan. My D-I-L and I round up sharing.