Right now, they don't know. They're going to learn very quickly when they want to use some website and they can't.
We agree it doesn't need to be 100% perfect. But it needs to be at least, like, 60% perfect, right? And unless you make it at least a bit hard to bypass, it will stop virtually no one.
Some undoubtedly will.
Installing a new browser is already a bit hard for most people. I think you are a little skewed in your thinking being online on HN.
You also aren't thinking about age. Certainly 16 and 18 year old probably can get a new browser installed. But a 14 year old? 12 year old? 10 year old? That barrier is a lot higher the younger a kid is.
I just finished my second year as a fifth grade teacher, so I have a lot of experience with ten year olds. I am confident a majority of my students would be able to install an alternative web browser if they needed to, and a majority of the remainder would ask a friend to do it.
To give you an example of the workarounds kids will find: Youtube was blocked on school laptops, so the kids all started embedding Youtube videos inside of Google Sheets in order to watch stuff. This isn't, like, something a few savvy kids did, it was a widespread and common practice.
And, in my opinion, a healthy thing for the kids to learn and do.
Lol. I started building computers, installing operating systems and tinkering with Linux between ages 10-12. I also started watching porn not long after that, and guess what, I still became a more or less normal adult. There is absolutely no need to "protect the children."