So do roads, and your metal cage literally has a code on a plaque tied directly to your government ID, with a retroreflective background and each character carefully engineered to be machine readable from any angle and lighting. Hell, a good number of the cars you pass have 360 degree camera arrays pointed directly in your windows, or if you spring for a higher end model with all the features, you get the privilege of a camera pointed straight at your face and at your passengers' faces.
Also, you can cover your face on transit with something like a medical mask and sunglasses. If you try covering your license plate you'll literally get arrested.