"Are you always there with them when they're on YouTube,"
That one. They currently have no independent access to YouTube. (Well... technically if they knew what buttons to push where they do. I'm not using high-tech to block them. But they don't know and I'm not teaching them yet.)
Even a few years ago I might have considered this a bit much. But since "Elsa-gate" my mind on that has been changed. I know it's not just a weird conspiracy theory or something because I've even seen a couple of them pop up in my "related videos" list myself, and I don't really have a viewing profile that looks like a kids profile. (The reason why Elsa-gate is happening may be conspiracy theory related, but the brute fact that it is a thing is something I've seen first hand in my own feeds.)
The increasingly aggressive targeting behavior across the Internet is I think something not to be taken lightly. Unfortunately we're going to have to raise our children to deal with it, but my considered opinion is that the best solution before the teen age years is to just cut it off entirely. It is not as if we are leaving them adrift, the only ones without tech in an increasingly technical world; my kids play Minecraft, they've seen enough of the current YouTube videos that they can discuss them at school, their school is using technology in a halfway sensible manner so the nine-year old can already type and the six-year-old is on the way. It's only certain segments of the Internet that they are better off just locked away from.
Heck, it's not even terribly hypocritical of me... I lock myself away from those very same segments for the very same reason! I use uBlock origin pretty extensively, and whenever I see one of those bullshit Taboola blocks, I'm actively annoyed that they are so tuned that I find myself wanting to click through myself. (I'll know I've gone senile when I no longer can resist it.) I'm not magically immune to this crap, and I know it, so I avoid it. I rely on my own discipline to do it. But relying on a pre-teen's discipline is probably not a good plan.