Should I write this???

So there are these people that we sometimes go out to eat with and I think that we won't be doing that any more. Let me explain. Every time we go out with them they complain about the food, the service, the menu, the price, ect....you get the picture. But they go even further than that. They are the kind of people that get their meal and eat 3/4 of it and then complain about it to the manager and refuse to pay for it, not just the one dish, but everything they have ordered. I understand if something is wrong and asking to have it fixed but that should be done when you receive the meal not after you have eaten most of it. They have done this more than once so much so that other people we are with or ourselves just cover the tab so that we don't have to suffer the embarrasment. I kinda want to talk to them about it but I really just don't have the nerve. I just hope their kid doesn't grow up thinking this is how it is done and that you don't have to pay for food at restaurants.