Could it be used as a sort of fingerprint to identify phones? I'm imagining using a scanner to create a list of phones in the area. You walk through the halls of congress to compile a list of devices. Do this every few days or over the course of a month, to eliminate visitors.

Now that you have your fingerprint, you can leave a few scanners around where you're trying to track the congressmen. IE, if you want to blackmail, put it around strip clubs.

Seems like a major security hole to me.