My niece is 14/15, and she gave all her bank account details to some guy on Tiktok who said he wanted to send her 5000$.

There is an absolute failure in the teaching of online safety and critical thinking. The fault lies mostly on the parents, absolutely, but it needs to be taught in schools, like taxes (my kid is currently learning about how to file taxes in one of his classes).

I've taught my kid about all types of things and the "why" behind it: don't click links in email or messages, spotting ragebait content & not engaging with it, what is & isn't appropriate to talk about with a stranger online, the intentions behind the actions and words of a potential predator, etc.

Teach your kid to question things. Always give an answer to "why", ALWAYS!!!! Because if you don't give access to the logic behind things, they will simply start to accept everything at face value without any thinking. Worse yet, if they don't believe there's logic behind your decisions and words, they will disregard your advice and simply do whatever they want.