The ruse is made more effective by making it appear that there is no hurry in accepting the wine. This may be one of the earliest uses of the concept of reverse psychology, where the impetus to do something is increased by suggesting that it be delayed. The ruse works, and the Lamanites indulge.
Much is now know of the ancient Maya since the translation of the glyphs, but none of them talk about drunkenness or problems with drunkenness. We don’t have good data until the time of the conquest, and that data is for the Aztecs. While it may not be directly applicable, we may yet presume some similarity with the older cultures based on the other traits that can be traced to the past. For the Aztecs we find very strict laws against drunkenness (Warwick Bray. Everyday Life of the Aztecs. Peter Bedrick Books, 1968, p. 41). Such severe laws, and particular the types of exemptions made (for the old and infirm, and certain festivals) tell us that this was something to be kept under tight control. Typically, laws are created to legislate where is a problem, and we may expect that the Aztec laws against drunkenness are an indication that there were known problems with drunkenness in the society.
Relative to the specific suggestion that the wine be reserved for the coming battle, there is interesting confirmation of a similar practice for the Aztecs. In a section of the Florentine Codex describing the characteristics of different types of drunks, we find a description of some of the people who were allowed to drink. In this case, we take notice of the warriors:
“…only those who could drink…. The intrepid warriors, the bold, the foolish, who paid the debt with their heads and their breasts. That is, they would ber captured sometime when war was declared; or else on issuing forth [to battle] they sould capture others and take prisoners. So [by drinking] they went about mocking death.” (Florentine Codex. University of Utah, 1957, 4:17. )
Apparently the addition of a little alcohol aided the warriors in bravely facing the battle to come, some where the liquid assistance might help them capture, some where it might help when they were captured. The Lamanite warriors may have had a similar practice, and it was to that practice that the spy was referring. In any case, this time the Lamanites decide not to defer, and they drink, clearly to excess.
Historical: The wine of Mesoamerica was the fermented juice of the maguey plant, known as octli.