That would be also nice, but given we can't make everyone to do the most basic interoperability I don't see it working…

As for: > Teens will easily bypass any method as many today watch porn

well, they do, but each obstacle discourage them to do that. It's like with chocolate while being on a diet - if you have it within reach next to you you are more likely to eat it; put it on a shelf which would require standing and walking - slighly less likely; put it in another room - even less; and if you don't have it in home and you would have dress up and take out the car and drive to the shop most likely you would just wave your hand at that :)

So no - it won't prevent it completely but I'd argue that it would significantly decrease the use :)