Oh, I think you folks are onto something. There were four of us (all adults) at the Poly pool one year. My husband went to the pool bar to get margaritas for our party. He came back with a little, green, plastic pail. And two empty plastic glasses. I asked him where our drinks were, and he stated, "In the pail." I looked at him kinda funny, and he said that they will only give two drinks to one person at a time -- and so the bartender gave him a pail's worth of drinks since the pail held more than two separate glasses. I had to go to the pool bar to get the "other" pail for the rest of our party. I found the whole thing amusing, but understood why Disney did it that way. Once again, looking out for the welfare of their guests. No complaints from me.
As to taking more than one drink from the concierge lounge, I haven't seen any signs yet (but I normally don't drink, so that is probably why I haven't noticed any).