When I teach yoga (瑜伽), I usually announce "Phones off and at the back of the room" at the beginning of class. Recently, I forgot and had to whisper to a student texting during class to turn off her phone. She looked displeased but did so. But two days later, in another class, I was met with resistance from a young woman who completely refused.
"But I'm on call. I might have to jump up and run out of class."
"Then maybe this isn't the best place for you to be tonight."
That response got me an angry and unfriendly look. But when she came back the next week, there was no phone and she was much more present.
Present is what I'm asking my students to be. Present to themselves and their yoga experience. You cannot be present to yoga if you are texting or emailing or anxiously awaiting a call. And neither can anyone around you. Definitely, if one phone is out, many pairs of eyes are drawn to it. And then other phones start to appear. Forget the fact that you're missing the class you paid for; you're at risk of losing your balance and hurting yourself or someone else due to inattention, or disturbing someone else's moment of peace and stillness with the clicking of your keys.
So please, do yourself and everyone around you, this teacher included, a favor and turn your phone off and put it away before you unroll your yoga mat. If you truly are on call, think hard before you come to class.
Be present for yourself, wherever you need to be.