tldr: if your kid keeps breaking the rules, ramping up enforcement is not going to change that for the same reasons that punitive punishment in the judicial system is not effective. Your kid has to understand why the rules are if they're ever going to function well within them, and that also requires a level of parental compassion and understanding that often isn't present.

> If your son keeps braking the rules you've set....surely there comes a point where he loses his phone/PC or whatever?

The efficacy of this depends wildly on how the rules are explained and enforced, I think. This is a topic that comes up often between my aunt and I. She has two kids about 10 and 13 years younger than I am, and often asks my father and I, the tech people of the family, how to enforce content filtering
and screen time limits for both kids. I've effectively refused to help on the basis that it'll only offer her a false sense of security, given that I was able to circumvent every control I faced with relative ease at the same age as her son. I felt that anything she tried to do on the "blind enforcement" angle would just encourage conflict with her oldest, who like me was rather technically inclined and often frustrated by parental oversight.

Note, I'm not a parent, just an adult with some frustrations over how this stuff was handled when I was a kid, so I'm sure there's blindspots and misconceptions here. Take all this with a grain of salt.

My mom embodied the philosophy of "these are the rules, and you lose privileges if you don't follow them." This most often came up in conflicts over technology. She would set rules over what kinds of games I could play (non violent only), when I could use the computer (not after like 7pm), and broadly how much time in a week I could spend on it (maybe 5 hours before I'd start getting pressure to hop off), in addition to the standard no-admin-rights and interent-content-filtering.

I'd often circumvent this stuff through a combination of linux boot disks and just messing with the BIOS clock.

Mom never really explained why the rules were what they were. Some I could extrapolate: the content filtering seemed to largely stem from her Puritan view of sex. Thou Shall Not, and no further discussion. The time-spent I was less clear on, but I think it was broadly just that "screen bad" and there were more interesting things to do in the world, in her opinion. For my part, games and computers were my only social connection to others, as an only child who lived across town from all his school friends. This means whenever I "lost privileges" for my phone/computer/etc, I was now socially isolated as well, which just made me more upset.

There certainly were times she took everything away, as a "loss of privileges" for breaking the rules, but then I just got more miserable because the root problems for me still weren't being addressed. Moreover, that meant she was constantly framed as an adversary: enforcing the rules as a single parent takes significant effort, because there's no outlet. I had nobody to vent to, she had no other adults for backup or to bounce ideas off of. Plus, I needed the thing for school often: writing papers for class, or looking up how to do my math problems. There came a point where, philosophically, it was difficult to physically take things away because I'd bought them with my own money or they were gifts from other family members.

Compare this to my dad's strategy: He knew there were plenty of things in the world he didn't want me having my life ruined by, so he went for education over prohibition: "You're too young for porn, because it gives you unrealistic expectations of both sex and relationships. Also it forms addictive habits. You can ask me questions, and I'll keep an eye on your internet usage in case I see anything we need to have a conversation about, but you should stay away from that." Infinitely more effective to a developing-me: now I understood his concerns, the goals, and had a method of recourse if I disagreed.

As an adult, I 100% understand that there's good damn reason to prevent kids from having unfettered access to the internet. Especially preteens and younger: holy crap, youtube is a brain-melting attention-hacking cesspool. Simultaneously, I think it's insanely unreasonable to "walled garden" everything off and call it a day. That's not how the world works, and if that's the chosen method of "safety" then you're just making it so your kids will never come to you with questions during their own exploring while also leaving them unprepared once they're outside of your bubble. I was always insanely frustrated that my mom didn't just talk to me, or when she did, that her beliefs and concerns were always more important than mine. Again, I get it: kids are not always rational, it is the job of the parent to watch out for forms of harm that kids aren't paying attention to, etc--but I still hold a lot of those frustrations as an adult, especially because I never felt like I got to voice them as a kid. So, I just went around them. Constantly.