Mexico (MEX and TLC) has secondary security at the gate. Ironically, while Mexico security will not allow my miniature bottles (especially handy for long tarmac delays when CO refuses to serve alcohol!) to clear security they have never questioned my duty free purchases which have been as large as a 3 litre bottle of Johnny Walker Black (wish they made the Blue that size, but then again, I probably couldnt afford it!).

In my experience, duty free purchases are delivered on the plane or for pickup by the passenger at the cabin door, so you shouldnt have any problem.

Why a 1 1/2 oz miniature bottle of booze isn't allowed but multiple 750ml, 1 liter, 1.75 liter, or larger bottles are is beyond me.

go figure that while US based carriers/security don't mind pax bringing liquor aboard, Mexico has a problem with bringing liquor aboard flights heading for the US. its just those type of things that make me drink........