As far as I am concerned, @Parakeetamol, what you do is not bad parenting - the opposite, in fact. I don’t expect parents to be able to predict their children’s behaviour correctly every time, and even the most well behaved child can have an off day - but what matters is that you deal with the situation positively - you try to stop the unacceptable behaviour, and if that doesn’t work, you all leave.
If I was in a restaurant near you, and you had the situation you describe, I would see a parent doing their best, and I would not think that you’d get fined because you are clearly parenting, unlike the parents in this story.