What you gonna tell them? "Okay kids, if you see boobs somewhere in the internet close your eyes..." Kids are curious, it is their nature. What would you do if you were a kid?

I would tell them about particular dangers like 50 year old strangers posing as 13 year olds... I remember very well what I felt about boobs when I was a kid and that's exactly why I have no worries whatsoever. There's an age where you're not interested and when you become interested, you'll be able to cope, and cope very very well :-)