IMO if you have to put an app on the phone to protect your kids, then maybe they are not ready yet for a smart phone. This has been my biggest pet peeve with kids today. I see kids walking around with smart phones when they are 5 and up. Basically you give them a tool that can access anything on the internet in a very portable system so you are not able to fully monitor their activity. It was bad enough when kids would be unsupervised on their parents computers.
Honestly, before the age of 15 I see no reason a kid should have a smart phone. Maybe a flip phone that can send and receive texts and calls, but the rest? Again, just my own opinion.
Well, I could take away the computer, because that can be used to surf porn or talk to predators. Also the Xbox, same reasons. Restrict the cable to only kids' channels, or only watching TV when I'm there monitoring everything...
Trust but verify. Kids will push their limits, even good kids. It's my responsibility to be their parent, to guide them, guard them, correct them and more. Even grown ass adults will do things they shouldn't do when they are alone or think they won't get caught... and we have systems set up to monitor them, too. Driving monitoring, phone restriction at work, internet blocks at work, etc. Guess those people shouldn't have a job, then, either, if they can't be trusted 100% on their own to do the right thing.
Just saying... yes, it's to each their own, but then, lots of people let their kids do anything and everything, monitoring nothing. I'm determined my kid will have more supervision than that. And I had a sister in law who wouldn't let her kids watch Smurfs or Harry Potter stuff because it was witchcraft... I don't want my kid to be a freak and overly sheltered, who then goes crazy when he turns 18 and goes off to college because he's never had any normal "kid" experiences, either.
To me and my wife, it's about balance, oversight and learning limits. That's all.