Whenever anyone does a search in Flock's database, Flock sends the metadata to the related customers.
I.e., if someone does a statewide lookup in Nebraska, all Nebraska-based Flock customers receive the search metadata. Ostensibly, to be able to track if "their" ALPR data has been queried. Those audit logs are public record.
This is also how IL discovered out-of-state agencies were using data from Illinois for immigration enforcement (after FOIA by a citizen, of course; apparently none of the IL law enforcement agencies audited their data for unlawful activity).
I.e., if someone does a statewide lookup in Nebraska, all Nebraska-based Flock customers receive the search metadata. Ostensibly, to be able to track if "their" ALPR data has been queried. Those audit logs are public record.
This is also how IL discovered out-of-state agencies were using data from Illinois for immigration enforcement (after FOIA by a citizen, of course; apparently none of the IL law enforcement agencies audited their data for unlawful activity).