some parent allow their child to operate gadget, and the other have own perspective. its bad if they just following what hype without knowing what it is, bad or good. parent have power to talk with them, tell about which the good way. sadly, many of them just ignore what child doing, like no problem if you grab phone a day as long as no problem, which can be interpreted to disturb the peace of parents.
There are tons of "how to raise a child" books out there and they all act as if a kid is not a person all of its own. One thing that works for a child may not work for another. I have read way too many bad stuff about bad kids that convinced me that there are some kids who are simply just born bad, and yes saying that is horrible for most people but let's be honest the growing up part is majority of the end result for a kid, but how they were born with plays a big role as well.
There are many people who go through similar stuff, and it reacts differently in every kid, hence why I imagine every kid can't be raised the same way neither. What I believe is that you should be a good person as much as you can be around them, teach them the value of life and how to be kind and nice to people, give them enough freedom to test their life and if they end up being good then that is great, if not then there is rarely anything you can do.