In my experience, at most TS restaurants, as soon as the server comes over they ask if you are on the DDP or have any discounts. If they just ask if we are on the DDP. I usually say no, but we have the DVC, Visa, AP, TIW or whatever discount we are using. For any of those, you wouldn't need to say anything about them until you paid the bill.
I normally mention it when they get ready to bring the bill. I wear my slider on my MB so there have been a few times the server has noticed it and mentioned the discount to me before I could.
I only mention it (and Tables in Wonderland) when its time to pay the bill. When the server asks if you are on a dining plan at the start of the meal its because they want to be sure you are aware of what is included.
I tell them AP or TiW when they ask if we are on a Dining Plan. That way they come get my card before they even run the bill, and it saves me the back and forth time to adjust the bill when it's time to go.
i always tell them that we have the TIW when they ask about the DDP. We have never had bad service. If anything, its been great.
There are 2 thoughts. 1 that the server doesn't care because their tip is locked in. 2 They have diners who care and give really good service. Maybe we have been lucky, but we have been in group 2.