As a server, I am expected to take ddp credits for those dining if there are 2 or 4 or whatever indicated on your card. It will also be noted when you book that you are DDP, when you are seated that you are DDP and when I receive your seating card that you are DDP (notice some overkill here). Personally, I have no problem when guests want to split up the group, pay oop for some and not for others. I fully expect and encourage them to share the apps and desserts that are presented to the ddp guests (this is also true for guests who are out of all but a few ddp coupons or guests who are bringing non-ddpers). To require you not to share would make you a rude diner.

I have had guests who are in a party of 3 but mom and adult daughter just don't feel up to eating much (heat can do that to you) and want to share, no problem.
The issue here is as follows, should I get audited (happens relatively regularly), I can be terminated immediately for not following company policy. I know of a handful of servers in my area who have been terminated for things relating to the DDP. At the same time, I am charged with the task of exceeding the guests expectations and doing nearly anything it takes to make them happy - big conflict here. Do I still bend the ddp rules - absolutely. Come in with a smile, good attitude and be friendly and I will do what I can to make your stay enjoyable. I can always play dumb as long as I limit how often I bend the rules. Once or twice I can get by with, regularly, I am fired. Biggest problem is your dining location of choice. Best bet would be to have a hubby and wife use plan and the other couple be "out" of the plan. Then have the other couple pay for dinner one night in a 1 TS location.
The whole point of the DDP was to fill the rooms and parks, keeping people on property and not losing revenue in those places. It was expected to be a loss in food and beverage, but they are doing what they can to minimize this loss. It is absolutely not a plan that is expected to boost the bottom line of the restaurants on property.