The idea is good, but there're a couple of ways to bypass any limitations within minutes. You can start apps from a notification bar even if the phone is locked (eg. WhatsApp). Then click on a link - web browser opens with the phone still locked. Or just run an app from extreme power saving mode. Are my kids smarter than Google programmers? These flaws make the app pretty much useless. Further even the always allowed apps are very often blocked for no apparent reason. It's one big joke.