Wirelessly posted (BlackBerry8830/4.5.0.138 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/105)

Until it died, I had a Palm with a still & video camera. The lens was on the back side up top. It was very easy to record while appearing to read email. Something like that would work nicely at close range. You could even place it in a bin face down (lens up) and leave it on all the way through the checkpoint.