I haven't read the article, but I think it's fair to say many of us have experienced the "coffee shop" scenario. One incident that springs to mind, a couple of years ago we were in Costa Coffee, Esher, two young children under five, with dad, were running riot round and round the tables, the shop was quite busy with customers carrying trays of hot drinks. Benevolent father just smiling at his offspring as if they were a complete joy to behold. In the end, one of the staff, and this doesn't happen very often because I find they are generally not very proactive in remonstrating with parents, actually came over and asked him to leave, which he did. This was a particularly extreme case. I did also witness a couple of very young children having a race against each other in not so crowded Marks cafe, still dangerous imo, oblivious mothers not taking any notice.
I would just like to add that I live in a communal development by the Thames and we have wonderful gardens where the children play outside in the summer, some of the older residents complain about the noise. My attitude in these circumstances, "is stop being such a grouch, they need to play outside and expend some energy" In cafes and restaurants it's unacceptable and I wouldn't have allowed my children or my gc to behave in a way that they would annoy other customers.