We ran into this a couple of years ago. I was dining at Via Napoli with friends who were on the DDP, but I had the TiW card. The waitress kept insisting that we each had to use a DDP credit and finally went to ask a manager, when I kept insisting I wasn't even on the DDP, so didn't even have a credit to use, and wanted to use the TiW card. She said she didn't think that was allowed, as only one discount could be used per table and the DDP was considered a discount.
When the manager finally came over, he rolled his eyes at her and told us it would not be a problem, that I could use my TiW card,
but each of them had to order their own entree as no sharing was allowed on the DDP. He then looked at me again and said, you will of course not be allowed to share their food, since you are not on the DDP. Duh, I wasn't planning to. What's funny is that I also ordered their fried veggie appetizer sampler for all of us to share and she was hesitant if she was then allowed to let me use my TiW discount for that, since I had shared it with people on the DDP. I told her to go ask the manager, if she had a problem with it, but someone paying OOP could share with anyone they wanted. The people on the DDP had eaten part of an appetizer that was paid for OOP, I had not touched any food paid for with the DDP. She said yeah, but that appetizer got a discount because of the TiW discount and she didn't know if that'd be allowed. She huffed and made a comment that they had a restaurant policy of people on the DDP, not being able to share, but she'd let us get away with it this one time.
That waitress was something else. Even though I had ordered more than they had, if I had reached for a sample off one of their plates, I think she probably would have slapped my hand. She was keeping such a close eye on us. lol