Due to the recent problems with tainted alcohol in parts of Mexico and our upcoming visit to Cabo, my friend was told by someone (the infamous "friend of a friend") to purchase alcohol at the duty free store in the Phoenix international terminal for our trip.

I was under the impression one cannot shop at a duty free shop in an American airport using an American passport, for flights to other countries. Am I mistaken, or was she given bad information?

I mean, this kind of makes a lot of sense, if it will work. We get to buy our alcohol, not worry about it getting broken in our luggage, not worry about going through TSA with too much liquid, not worry about it being tainted (I know, I know, it was mostly Cancun and PDC where the gov't seized 10k gallons...that's just not a discussion worth having with my friend). With the added bonus that we won't have to stop on our drive from SJC to our hotel in order to buy booze for our rooms.

This is either brilliant or 100% impossible. Can we shop at duty free in a US airport with a US passport?