I'm a parent, not a teacher - but I'm in no way surprised to hear that DS's school is way more lax than most going by the responses on this thread 
Rules in his school state that mobiles should not be used during class, but are free for use at all other times, however pupils are not allowed to be "plugged in" at any time on school property - whether that be with a phone, iPod, iPad, whatever.
In reality - even the S1s use them in class and half the school is "plugged in" walking around the corridors. Many (according to DS) will just put one headphone in, but that's the "good kids" who don't want to get into trouble - everyone else just puts both in and no-one cares.
He has been encouraged by staff to use his phone in class to take photos of notes or test results etc, as well as to take down reminders of passwords or work to be done. (Despite all work being set on google classroom)
I hate it - but it's indicative of much bigger problems at the school and my guess is that the SLT think it's a minor thing that's not worth policing properly.
(This is also the school whose smoking rule simply states "no smoking on school grounds" and that's it - they have even gone as far as saying that once the pupils are outside school boundaries, on the street, they have no jurisdiction over them so can't force them to do (or not do) anything, so they can't stop them smoking even if they wanted to. The pupils are all allowed out of school grounds to walk into town for lunch and it's not uncommon to see kids as young as S2 smoking openly while out at lunch time.)
In case it's not obvious - I'm not a fan of our SLT