16. Smile for the Detector

Metal detectors are notoriously sensitive, and many things can trigger them, from belt buckles to dental work. However, if you’re wearing a metal “grill,” you’re almost certainly going to set off the alarm.
While grills are allowed on planes, TSA suggests removing them before you walk through the scanner. It saves everyone a lot of time and prevents you from having to explain your dental jewelry to a room full of strangers.