I'm sympathetic. But given the article is against "fact-free" parenting. I didn't find the data presented very compelling. Basically you'd need to know how common crime against children traveling unsupervised on buses in a similar scenario. The closest example presented is kids in New York riding the subway, so presenting stats on that would be useful. I'd also like more details on the Japanese example, it's honestly…
Hearing reports of a thing on the news is actually a signal that such things are not common. That's why you don't see every little (or even big) traffic accident on the news. It's not special. It happens every day.
Obviously, if you're using it to set policy, some kind of study would be valuable.