Not that you heard it from me (nudge-nudge, wink-wink), but what we did last year was order either a diet coke or sprite or VIRGIN margs, etc., then we'd have a nondescript runners type plastic reusable water bottle (colored, not clear), and then after the waiter was gone, we'd spike our drinks with whatever. We kept one in my friend's purse and one in my tote, which had my iPad or whatever to look like it was a legit bag I needed to carry around.
At each place we were at, we didn't try to make it obvious, we made sure other customers couldn't figure out what we were doing, but the staff probably knew. It was sort of a "don't ask don't tell" policy. But everything was pretty empty and we were tipping well, so it all worked out. It was kinda' heart-breaking to see them turn away group after group of booze-seeking tourists away.
The scene at the Super Ley on the Friday before it closed was a madhouse! Make sure you get there before the shelves are empty, but really, there's not much of a reason to bring a ton of beer down from the U.S., don't risk the chance you'll get a greedy border guard. What is it, like a six-pack per adult? And if you've got one of "those" people on your trip, you can pretty much buy any American beer down there at the Circle K or whatever.
