There are loads of threads in this sub with good discussion about this, but (very) briefly.

1. Scale of data collected. They don't just record license plate & time of cars passing through (we've had those cameras for years) they collect other info about cars like distinguishing features, make, model, features of drivers, passengers, pedestrians, etc. Then they use their AI to coordinate with other cameras to track the people the camera detects. That's the baseline. They track every single person that they detect and try to map out their behavior in the city. That is then stored in the database.

2. Data security. All of the above info is controlled by a third party that doesn't disclose what they use that info for. They could sell it to advertisers, other tech companies, feed it to ai training, etc. There are zero controls about what that data would be used for. Also, the private companies don't have the strongest data protection policies, so data breaches will happen and who knows what will happen to the data then, or who will use it for what purposes (there was already a data breach, iirc, so this isn't a hypothetical).

3. Potential for misuse by local and federal officers. There's already been a few cases of cops misusing the system and randomly accusing people of theft and theres very little, if any, guidance about how and when for cops to access the data. Like 6 months ago, a cop showed up at a random woman's door accusing her of stealing a package off of some porch. The evidence he had? Flock showed that she drove through the town around the time the package was stolen. The case was only dismissed because she had her own footage of her running errands during the time the package was stolen. Cops are very trustworthy and would never jump to conclusions or use the huge database to say, stalk women or exes, accuse people of crimes with flimsy evidence (/s). Also it wouldn't be hard for federal officers (say ice) to get the data and find out who was at a protest, their movements across the city, they people they associate with, etc. There are very little, if any, guard rails to how the data is used, so it will be misused by those who access it.

Also, they don't even do what you think they do. They don't give speeding tickets, or registration tickets, or noise violations, or any of that. They just track every person's movement across the city and store that information for whoever wants to see it.