Defendants trying to exclude ALPR evidence often invoke Carpenter v. U.S. (or U.S. v. Jones, but that’s questionable because the majority decision is based on the trespass interpretation of the 4th Amendment rather than the Katz test). Judges have not generally agreed with defendants that ALPR (either the license plate capture itself or the database lookup) resembles the CSLI in Carpenter or the GPS tracker in Jones. A high enough density of Flock cameras may make the Carpenter-like arguments more compelling, though.