Just a couple of quick points to consider.
The laws are different from state to state, even within a state. Utah, for example, the bars can (and do) get sued for fake IDs. There wasn't a lot of personal responsibility for someone with a fake until this past legislative session.
Secondly, having had a hand in producing some scanning software to work with Utah Law (there are only so many items you're allowed to pull out of the license from the mag stripe or the bar code), what gets pulled also differs from locale to locale. For example, here you're not allowed to pull address or SSN. British Columbia likely has the same constraints, as do most states in the Union.
And finally, it's really not that difficult to fool a scanner. I had one test card that looked legit; Utah's State Seal hologram was fine, the plastic was not obviously tampered with, paper looked fine as did the type, but upon scanning the information printed on the card was obviously not what was coming out of the display using information pulled from the barcode. A "22" year old white male from Provo was, according to the software, a 37 year old female from Ogden; so just having a red light/green light system would not work.
Take into consideration, none of this interacted with an online database. Information on the bar codes and magnetic stripes are ridiculously easy to read and code/decode.
Side note, it's Friday, it's quitting time, so I'm going to go make sure my license works at a few fine establishments with loose womens and beer.