I figured out why hard liquors can lower bg. It is because glycogen is constantly produced in the liver and the adsorption of alcohol stops this production. If you continue to receive insulin from your basal rates on the pump/ lantus, and have not eaten anything, the sugar is lowered because glycogen is not being produced. Even if the drink has carbs, the bg can go low.
That said, does anybody know the best way to drinking/ not going unconscious. I know someone who has been found twice unconscious while drinking, not from alcohol, but from low bg.