As a follow up, it seems pretty easy to carry wine around in your carry-on luggage WITHIN Argentina. They just don't seem to care about liquids.
In a rather funny scene, I was returning to BA from Mendoza with about 4 bottles of wine in my carry on luggage (small winery stuff that I'd never find in BA). The x-ray operator was very thorough: they wanted to see the plastic knife I had in my suitcase (which turned out to be OK), as well as the 50 cent plastic corkscrew (which they confiscated). But the wine -- no problem!
LAN did not enforce their carry on baggage limits. My wife and I each carried a rollerboard and a backpack. We printed boarding passes off the LAN website (remember to print 2 copies). Nobody said a word about our luggage in each direction from BA to Mendoza.