Solving problems is what you do after you learn to code. A kid is still just poking and experimenting, and a hard lockout is, in my experience as a kid myself, a great way to kill that excitement.
I'm not saying you shouldn't have regular breaks, I'm saying a kid should have leeway to use e.g. half an hour more and then do a longer break, not feel a pressure to finish stuff in a hurry before it locks out.
Schools use timed breaks and in rare cases of interesting classes they do not discourage students to learn.
Obviously we have very different experiences.
3. Timed lockout is not target, invented just to prevent illness, it is also a method. Method to teach self discipline, even to begin teaching self discipline in some cases. No one will tell you how to optimize living when you'll grow up, that is why we read a lot of articles about people who burn out on a job.
First, I'm not opposed to lockouts. I'm opposed to inflexible, computer enforced lockouts.
Secondly, is there any evidence that timed lockouts actually help with self discipline?