Sorry I guess I wasn't clear enough but no random online people they meet online aren't included in the heading people they know.
People they know means people with much closer social ties. Basically it's people who are in a trusted position of power.
This is not to say that you still don't need to worry about it but it's very unlikely your kid is going to meet somebody randomly online and get taken advantage of there.
It is infinitely more likely that a priest or a counselor or a medical quack is going to be the one taking advantage of your kids and what's worse you are likely to facilitate that unknowingly.
Parents know to watch out for random weirdos. And they teach their kids that. What they don't do is teach their kids to recognize when they are being taken advantage of by somebody who is trusted.
This is also by the way why the right wing religious extremists oppose sex education. Sex ed teaches kids when they were being abused and religious extremists want to keep the abuse on the down low.
The bottom line is we continue to ignore the primary vector of attack because well, I don't know the fuck why. Seriously.
Colorado for example passed a law requiring priests to report when they were told about child sex abuse and the priests managed to get the law overturned.
There is absolutely no reason for the priests to want to do that except that they want to be able to hide child sex predators inside their ranks.
Again I cannot comprehend why except maybe, and I'm literally just making wild guesses but this is the only one I can come up with, they have so many sex predators that they cannot imagine rooting them all out. That it would fundamentally break their organization if they tried.