> Having these keep data for a very short amount of time is a reasonable idea.

I agree that this is more reasonable than the status quo (although I’d still prefer no cameras at all). Now show me the politicians who are willing to limit ALPR data retention by law on the federal level. As far as I know it hasn’t even been proposed, nor will it be, until some kind of major public scandal emerges. I’d rather not wait until major harm is done.

The federal government has an unfortunate habit of illegally harassing the disfavored group du jour (which rotates about once a decade). State and local governments are often worse, with personal grudges getting into the mix. I’d rather not provide tools to make the harassment even more effective! At some point you begin to enable new “official” crime with the tools you use to stop typical criminals. And the impact of state-level crimes can be much larger and more widespread.

> I think you’ll be surprised how much real people don’t have cartoon villain ambitions.

Most don’t, but some do, and unfortunately they are attracted to power like moths to a flame. Not that everyone in government is a bad guy, but many are when given means and motive.

Edit: edited to specify data retention at the federal level, actually I was surprised to see that a few states do limit data retention.