The problem I have with people using iPads as cameras isn't how it looks. It's how it impacts those around them. When people use cameras/phones to take pictures, they typically hold them in front of their face so they can look at the viewscreen. With iPads, people often hold them up over their heads which blocks the view of guests behind them. Also, the screens can be pretty bright, especially on dark rides or outdoors at night. Many times I've had my view of an attraction or show impacted by the bright light shining in my face from the iPad in front of me.
If you are going to use your iPad, that's fine, but please turn down the brightness and hold the iPad in front of your body, not up over your head.
As for the standing up in a moving car issue, I'll have to agree to disagree with those of you who don't see a problem with that. I agree that kids see all kinds of stupidity on TV and movies but as a parent, I feel it's my job to teach my daughter right from wrong. That largely happens by modeling good behavior, not mimicking the bad behavior.