Comment by capote

Nah, I'm sayin the area leading up to passport control or in the baggage claim area. I realize once you're sure something sketchy is happening, there's no actions left to take anymore. I pretty much have my phone out and in my left hand 100% of the time I'm in airports/planes, so nothing suspicious about right as someone's coming up to you or right as you walk up to a CBP officer you just tap a button.