"We are not legally permitted to blanket surveil/ALPR entire neighborhoods/towns, etc. ...

... and we can't pay a private company to do this for us ...

... but nothing prevents us from paying a private company who is doing it already, to give us that data."

The line between the last two is blurry but also utilized - you can't put out an RFP for a company to capture such data that you're not permitted to, but if that company is doing it because it sees a/your market for it, then it's a free-for-all.