Was Enemy of the State the movie with the regular guy who had tracking devices in his clothes?
Since these RFID chips are so cheap, a lot of product packaging is expected to start using them for "inventory" purposes or something like that. I wouldn't doubt it if the government were to mandate RFID chips be installed in the manufacturing of shoes (for inventory purposes of course). It would just happen that these could be read from 30 feet away.
It wouldn't be rocket science for the RFID in your shoes to be matched to the RFID in your driver's license. Then, even if you don't have your driver's license with you, you could be identified 30 feet away by your shoes. Or if not from 30 feet away, maybe by walking through the door of a building. Or stepping on a sidewalk that has RFID sensors.
The potential uses for RFID are limitless. Isn't it the USA Patriot Act that gives the power to DHS to do just about anything it pleases?