It's a little more than that, though... remember the story with the Glasshole in the bar from last month who got attacked?
I seem to remember that the problem was some patron was aggressively annoyed that the glass-user might be filming them so the glass-users response was to start filming them. The problem was bery much idiots in that case.
The video starts with the patrons already attacking the Glasshole, so no, she started filming them after she was attacked. And frankly, filming people committing a crime is quite a reasonable response.
That bar - along with most bars - have security cameras. Cameras that are casually pointed at people the whole time.
No, they are qualatatively different. The cameras go on a loop, old data is discarded...
Unless you own the bar, you don't know that for sure.
... and no one looks at it unless something happens. Most of it is forgotten, not uploaded to a company which rather creepily claimed to want go right up to the border of being creepy (Schmidt's words, not mine), or be plasteres on the persons blog in perpetuity.
That's also true for most people's blogs - no one looks at them unless something happens like, say, some idiot attacks the person with the camera and blog.
Taking a photo (with the flash off) can look exactly like the person is texting.
If you're taking a picture of the floor, or a selfie from a very strange angle, then sure. To take a photograph of anything interesting, you need to hold the phone up and that's obvious.
Here is literally the first result for a Google Image Search for "people texting". The three on the left are indistinguishable from people taking pictures. Flip through that search and I'd say about half of the photos have people holding their phone up in front of their faces. Point being that while some people text while holding their phone down at their waist, apparently just as many do it while holding the phone up to their eyes.