In my school the teacher locked them under the desk and brought them to the Principal’s office after class.

I never heard that any phone got stolen

Did the teachers stole the phones or how did that even happen? 💀

as the kids just take them out as soon as the teacher turns their back

When I was in school the teacher’s were seizing the phone if they caught you with it in class and sometimes require your parents to pick it up after school

I am not so much into programming, but what extra skill is required to add a license and make the repo public? Maybe if you have a closed source dependency and would need to replace it, then it would be a skill issue.

Are there any relevant/common reason to keep an app closed source if its NOT for profit?