Facial recognition technology is increasingly being deployed by police officers across the U.S., but the scope of its use has been hard to pin down.

In Miami, it’s used for cases big and exceedingly small, as one case Reason recently reviewed showed: Miami police used facial recognition technology to identify a homeless man who refused to give his name to an officer. That man was arrested, but prosecutors quickly dropped the case after determining the officer lacked probable cause for the arrest.