I have eaten in groups both of Witnesses and non-Witnesses. I have never had such bad experiences as when with Witnesses and this goes back to when I first went out in groups of young ones 25+ years ago.
I recently made the statement that Witnesses are often as tight as a gnat's chuff and there is nothing like a group meal to bring that out. I've seen it time and time again and it continues. My daughter recently went out and a load left paid their "share" and left as soon as the bill arrived, leaving the table £100 short! As usual one person stumped it up and is now trying to get the cash back from a bunch of other people.
Friends of ours had a problem with just 4 people. They were out, everyone ate the meal with no complaints then one couple said they were only going to pay half because the meal was not what they expected. They stood their ground and let their "friends" stump up the excess to save any more embarrassment. Needless to say they've not eaten together since.
It's shocking, childish and embarrassing to see how poorly Witnesses behave in restaurants.