A client in the restaurant industry brought this up to me recently: "I bought a fingerprint clock, put it in the kitchen, and an employee refused to register. Can I force them?". Short answer: no, not like that. Fingerprints, faces, and hand geometry are personal data protected by Law 25.326, and installing a biometric reader without further ado is the fastest way to get hit with a complaint before the AAIP. Here I explain what the Argentine regulation requires, what risks poorly implemented biometrics carry, and what alternatives exist to control attendance without stepping on the law.