That is a very inspirational story! I too am surprised they listened, but I guess it makes sense. The kids likely acted the way they did because they were completely comfortable around their mother. In contrast, they would likely be less inclined to test the boundaries of an imposing stranger who they are completely unfamiliar and uncomfortable with. Next time I find an annoying crowd of children at a zoo, I will test out your technique.
It’s similar to when you’re at a theme park and you see someone cut the line. They know what they’re doing is wrong and will usually back down very quickly if challenged. I won’t hesitate to tell someone to get to the back of the line if it’s going to impact my wait time.
As in any situation, I’d urge all users to use commonsense when tackling challenging behaviour. Be firm, but calm. Don’t be threatening or confrontational (the aim is to diffuse rather than escalate); and don’t put yourself in a situation where you could be putting your safety at risk.
In some cases, people are open to hearing an explanation and can learn from the experience e.g. you’re more likely to see the Fishing cat if you don’t attempt to break the sound barrier while standing outside it’s exhibit.