When a student was upset with me last year, she tweeted about it. I confronted her, and she showed absolutely no remorse. "Everybody's doing it," was her comment.
I also am reminded of a teacher, I think it was in Florida, who put pictures of her vacation on Facebook. She was drinking, and I believe a coworker turned her in. She was terminated because she was friends with both students and parents on Facebook, and they did not think this was the type of image they wanted to communicate for their school.
Finally, I have family members who pull out their phones whenever and wherever they can. Good old-fashioned eye-to-eye conversations are becoming obsolete. Go to any school party or even, more students are sitting looking at their phone than they are actually participating in the event.
You have covered all of the bases. The stories about teachers and their bad behaviors on their own time exposed to the world are very disheartening. One teacher that I know of was recorded ignoring bad behavior in her room by a student with a cell phone. All students should have cell phones put away during class time.