On a recent set of flights on a Chinese airline, I was asked if I would like a photo taken with the crew, with one crew member taking the photo on my phone.

The next day (same airline/different crew), I was taking a photo on the same phone (plane mode on) and was told that I wasn't allowed to use my phone at all as it could still be used to make emergency calls. She was very polite and apologetic about it. She said I could take photos on my tablet though.

I've been on plenty of flights where the crew have seen me taking photos, and had many occasions where the crew have offered to take my photo.

Seems that there is plenty of good photo friendly crews out there, but also many crew that don't like photos, either to show their power, or because they genuinely believe there is a safety risk involved.