We spoke with a member of the security team at Aria, who explained to us that "The Book" is a manual issued by the U.S. Treasury. (At least, that is what he thought, although we couldn't find any mention of such a book in the Treasury's list of official publications. We did, however, come across a similar-sounding volume, published by an independent source, but with controlled distribution only to verified law-enforcement and other recognized government officials and security personnel, which might well be the tome in question.) Whoever it is that produces this book, it lists all currently legitimate forms of government-issued international ID, including passports and drivers licenses, and is the go-to guide for all casino and nightclub personnel. We don't know what else is in it, but evidently that Massachussetts Liquor ID is not.
As a rule of thumb, the only forms of identification that are guaranteed to be accepted for proof of age in Nevada are specific state or government-issued photo IDs (a birth certificate does not qualify), including: a valid drivers licence; a valid military I.D.; or a passport issued by the government of a recognized foreign nation. While the Nevada DMV offers a non-drivers photo-identification card that's valid for proof-of-age here, where it's familiar to those required to verify its validity, there's no guarantee that equivalent state-issued IDs from elsewhere will be accepted; imagine how difficult it would be for those front-line security personnel to keep up to speed with all of the changes that take place on a regular basis to the look of each individual state's multiple current IDs?
With the penalties for a property serving liquor or dealing games to a minor being as severe as they are -- including loss of operating license -- it's just too risky to take a chance on accepting an obscure state ID. Still, in a town like Las Vegas, which is subject to so much foreign tourism, the acceptance of government-issued foreign IDs is somewhat of a necessity. The party at Aria with whom we spoke offered his understanding that visitors are nervous about walking around with their passports and explained that at his property at least, a valid international drivers license would be accepted in its place (hence, the need for The Book.)
We checked with some other jurisdictions and in Atlantic City it's the same: You must carry a valid state-issued ID, military ID, or passport. For foreigners, your drivers license will not be accepted, at least not at the Tropicana, where we checked. Evidently it's seen as too complicated or time-consuming for front-of-house staff to have to look up and verify such IDs manually (it's not as if security can hook up to national government databases in Japan or Argentina or Italy to verify that your license is kosher, although surveillance can hook up to an international database of biometrically identified casino undesirables).
At tribal casinos, it tends to be somewhat more flexible, and we've seen acceptable proof-of-age IDs listed that include valid state-issued photo ID or drivers license, valid passport, military identification, Merchant Marine identification, international drivers license, or resident-alien registration (green) card.
The only valid IDs accepted at Ontario's casinos are passport, drivers license, or official non-drivers photo ID. Although it's an officially issued photo ID, the health card is not acceptable as proof of age, while a previously issued "Age of Majority" card has been discontinued. Here, however, the provincial liquor retailer (LCBO) has a similar-sounding card to that Massachusetts "Liquor ID" card called a BYID (Bring Your ID), which indicates that the bearer is of legal drinking age. This, however, is valid only in Ontario, where that drinking age is 19.