ICE is using facial recognition tech on US citizens without their consent, according to DHS documents obtained by 404 Media. Despite such software's unreliability, agents may ignore a citizen's birth certificate if the app says they're in the US illegally.
Facial recognition can use nose bridge characteristics, eye distance, eye angle, eye color, etc.
Gait detection can also fingerprint.
Document everything and there will be accountability.
If possible, use a zoom lens and get closeups of their eyes. They are unique signatures.