Geek toy du jour - Grin with cat attached — LiveJournal
I'm guessing the message from remote to badge is not cryptographically authenticated. So it can't be that hard to program other people's badges, remotely and covertly... how long would it take them to notice?
"point the IR remote at the back of the LED badge, push one of the buttons, and a new message is set to display on the scrolling badge."
Bit of a challenge ;)