Not an electronics expert at all, but what are the chances of doing routine patrols or setting up checkpoints around airports to 'sniff' for the electromagnetic field emissions that these sorts of devices emit when used? I am presuming that they would have a fairly unique fingerprint that would make them stand out from the usual microwave or infrared noise that most household electronic devices use?
Oh, a very distinctive fingerprint! Big powerful EM spike at 564 Terahertz. Trouble is, it comes out in a tight collimated beam...
In all seriousness - besides the light, I wouldn't expect any emissions of any kind really. It's a DC battery and a diode. The only oscillator is the laser cavity.
