I didn't find any problems with service while on DDP. I did make a point of adding extra for exemplary service, but didn't even hint it was a possibility. If people regularly add a bit when it's warranted, maybe the "problems" will go away.
To be honest, I have seen people treat their servers horribly throughout their meal and then leave the restaurant loudly berating the service they got "because of being on DDP"! If I had been their server, they'd've been lucky to see their food at all [recognizing this, I don't work in the service industry :lol:].
I am always polite with servers, they have a job to do. I say "please" when I order and "thank you" when they deliver. I say "excuse me" if I need their attention or there's a problem with something and say "thank you" when they've listened to whatever it is that's a problem. The only time I've ever had bad service wasn't in a Disney restaurant, it was here at home. A girl was very slow in getting meals when they were ready in the kitchen, getting bills to people when they were finished, etc... I took a moment to ask her if she was OK and she broke down in tears, her father was in the hospital and she really didn't want to be working, but the restaurant was short-handed. She hadn't even told her Manager. I told her Manager, he gave her the rest of the night off and I drove her to the hospital to be with her dad. I also gave her her tip before she got out of the car.