This all leads to the bigger and more important issue: We should not be letting companies decide how much privacy we deserve... It shouldn't be up to Flock or any other ALPR vendor to decide how long police can collect and retain data
No, the bigger and more important issue is that we should not be letting anyone retain that data. If you want to do ALPR there is one and only one correct way to do it: You build a list of license plates you want information about after getting warrants about them, that list is sent to the point of recognition whether it's a camera or a data center, and any data about any plate not that list is not stored. There is no other way to fix the problem besides not collecting the data in the first place, period.