A guilty conscience isn't going to change much. Plenty of people feel massive shame using pornography and still use it.
Bear in mind, that because he was "caught" it is a possibility that he will cover his tracks in the future. This could be anything from selectively deleting history, to using private browser sessions (which you can ask for that info from your provider). Unfortunately there are more "clandestine" methods for this issue.
I don't see any reason why they need to have a smartphone as someone else said. A flip phone works just as well for emergencies (in my view better). They are not gone and I could find you many place in the US where you can get one. Grocery stores in fact. That's just my opinion, but I didn't need one when I was 13, it was a status thing. Could have easily had an emergency phone with only texting/calling.
It really depends on their needs, but there aren't too many practical uses for a smartphone as a child other than games and social media...which a LOT goes on there that is hard to monitor. Sure they might moan and complain, but "friends" is a ridiculous excuse because a lot of those people aren't "friends" they are internet friends and out of all my time on the net, actual friends are pretty sparse.
With Tmobile they have an explicit content block. I'm sure that's standard across carriers. The issue is wifi though, do you have wifi? If so, you can easily track everything that is visited on your wifi. You also have broad discretionary spying ability on your children's phones through the network.
You could try that if you want to...they said they'd stop, so there ya go. However, this is like crack and quite difficult to resist initially, I don't care what kind of christian you are, it's a new thing that hasn't really existed before. It wasn't until the advent of the net that it was "practical" and nowadays almost all of it is free.
Almost all these content blockers can be proxied, and I'm guessing that children are getting smarter. There are ways around all of these blocks.
Adsense I had at university and it blocked a lot of sites, but any explicit site it would hijack the speakers and blast a loud alarm system...pretty effective.
Also, if you use a home computer option...there are ways to hide history and bypass censors.
However, I will say that there are ironclad ways that no child is going to be able to get around and if you are interested I will share them. Unless they are a tech genius ofc...you would have to know how to program to bypass some of these things but it requires
you to be the monitor, not some other program. To put these protocols in place requires very little know how...but some understanding so you don't leave your own system vulnerable.
It could be simple history monitoring works for a while, but there is a very secretive element to this particular type of sin
Oh, friend of mine was required to use the computer in the family room, and as an administrator just change the password after you go to bed, pretty simple. What they miss out on from lack of internet pales in comparison to what is gained. It will chafe for them, but I would do all these things without a second thought. My own personal methods, are very akin to "big brother" and since I am not a parent I can't make that call right now until I'm there...but I imagine, it will be no privacy with technology but hopefully not militant to the point where they rebel and ideally they can see how I am protecting them.
This is an extremely difficult issue for some, so while it could be that simple measures are effective, it's a shortcut to fake sexual experiences that cannot ever be had in a similar fashion in their lives, to the point where you also cannot take it lightly hoping the Lord will work it out. He can, but based off my own life, it's more of a reap what you sow thing after a certain point and if he does bless me with children, well...I'm not sleeping in the same room with them, but they won't have the internet behind closed doors. Ideally, by the time they are adults, they see the wisdom in that and have made solid purity commitments.
When I was that age, videos were VERY hard to find. You won't be able to stop all pictures or softcore with these apps though as a fair warning.
With what technology actually can be used for, if they have a phone on them it would be very unlikely you wouldn't know exactly what they are doing at any given moment, it's just privacy is a personal decision.
Looking back, I would have liked for my parents to have been more savvy. I'm not going to give a testimonial at present, but there was no reason I needed an unblocked cell phone or my own laptop. Even in college, I had library computers to get work done, and I had a few times where having my own was uh not wise. If a child can give a legitimate reason why they don't need monitored internet, I'd love to hear it.
Oh and btw, today as a 16 year old, one could just walk into any supermarket, buy a phone with cash and service with cash and have internet, you would have no control. It is fortunate I didn't live today as a child. Then again though, the Lord has a way of blocking rebellious children, so there is that