I'm 65,My children are adult.
When I was young, not everyone even had access to a home phone much less mobiles or internet. My kids didn't either, although by then everyone had home phones and reps had car phones the size of briefcases.
When I was a kid I obeyed rules I understood and (kind of) agreed with. I worked round those I didn't. My parents never knew. I got into a few dangerous situations but I would never tell my parents, because the result would be restrictions. A man tried to get me into his car at 13. I stood back against the wall away from the car. I stayed polite but wouldn't go closer to the car, eventually he gave up.
I was pretty open with my kids as I knew that forbidding things didn't work. This worked for me, most of the time. I told them why I didn't think they should do things but that in the end I wouldn't physically stop them. Once they got older they told me things I didn't know. They knew my views and, even though I wouldn't forbid, they decided it was better not to tell me.
I grew up safe, so did they, so will most of today's youngsters.
Forbidding things doesn't work in the long run. Sooner or later they are going to have to make their own decisions. Staying open, discussing and educating means they are more likely to make good decisions that work for them. And that you are more likely to be trusted to give them guidance and support.
Clearly this has to be age appropriate - and that isn't a number. Kids mature at different ages.