I’d say if you are in a school taking lessons, you shouldn’t be checking your alerts outside of emergency situations.
In meetings, I avoid taking notes on my phone as it looks like I am sat texting.
My Watch gets a few notifications, but I am reducing them as when I get an alert I check, and have noticed a couple of people apologising for taking my time up (it looks like I am passive aggressively checking my watch).
So. If you’re talking to someone, don’t check your devices unless it’s urgent. Always apologise for doing so.
I have far too many colleagues who sit behind a laptop in meetings or on their phone. They look like they’re not listening, and even with the best of intentions they can get easily distracted.
Last point from me. I really want to type notes in meetings, but am trying to find the balance between attentive typing and handwriting. My notes are far easier to refer to when typed, but I am more alert when writing. I am still trying to find the right balance on this one!