I think they are just unaware that they are being photographed, otherwise they will be upset also, for sure.
This is something that I don’t know often, that’s why it gave me anxiety just to take these photos. I’m not sure if I will ever do this again lol.
By the way, I think you’re right about them doing or making a bad posture. It is unfortunate that these days people become enslaved by their phones. Much as possible, I simply stay away from my phone and take a little nap while I’m in the transit.
Yeah I would simply just try to ask first before taking a picture, or like you said be very calm about it so they aren't aware of it!
Asking about it… And definitely get me a 100% “no” 😅
The only chance for me is to be sneaky about it