alt Hacker NewsThe "cashier standard" you advocate for has already crept toward centralized state tracking in places like Utah. When you go to a restaurant and order a drink, the staff are required to take it to the back and scan it for verification. The scanned data is also compared with a state database of DUI offenders. It's not clear whether the database is stored on site, or if that data goes out on the wire for the check; presumably the latter. Scanned data is also stored for up to 7 days by the restaurant, and it's easy to imagine further creep upping that storage bound.
This is not the case in most of the country. Utah is largely influenced by a Mormon / LDS culture that expresses heavy opposition to drinking. I am clearly not proposing that the cards be scanned Utah style, I am proposing that they be glanced at by a cashier, everywhere else style.