I just took a trip for work. I saw the dumbest thing: a sign at the TSA checkpoint with a bar code on it. They invited me to scan the code with my phone to see a video explaining security procedures to kids. Right in front of the X-ray machine and metal detector.
I'm pretty sure if I had whipped out my phone and turned it back on, they would have been kind of grumpy about me taking a photo of the security checkpoint. Not to mention the timing of watching a video about kids and shoes and xrays right before the xray machine.
I'm not the only one who thinks this is dumb. Luckily, those other folks took pictures of the signs in action, so you can see what they look like. (Although these aren't the one I saw.)