I made my first international return without being scared of the import duty and I am only left with more questions. I arrived at PHX with 3 liters of tequila which I made known at both immigration and customs. Customs told me not to do it again which I initially thought was a joking way of approaching his desire to avoid the paperwork. I asked what the duty would be for future trips and again told not to do it again with an explanation that Arizona does not allow CBP to collect the duty and per the letter of the law I should be forced to dispose of the excess.

First is this true? I am having some difficulty grasping a state preventing the federal government from collecting a federal tax.

Second, is there a list of these local restrictions by port of entry? DFW and JFK are in my next ports so particularly curious about those before I buy a case of wine.