In some places where I’ve lived, local LE mounts ALPR systems atop most of their fleet. Those read “formal” plates as vehicles pass near the cruiser, and they proactively alert against a watchlist. Which presumably somebody’s hooked up to periodically ingest lists of recent lapses alongside the usual stolen/wanted/pile-of-unpaid-tickets sorts of stuff.

My sense is that such systems are rather less consistent at reading temp tags, and that temp tag issuance tends to be decentralized/dealer-based, rather more ad hoc, and thus rather less legible for semi-automated enforcement purposes.