It amazes me how many people think someone is looking. They have their hands full fighting actual illegal drugs. Ive never heard of anyone fined or arrested for shipping a few tins. Within borders there are no customs forms. This means someone had to go to the trouble of checking. Im not saying break the law...its up to you. But I bet you exceed the speed limit once in a while.
USPS handles 24 million packages a day.
Drug trafficking in the United States is all too common. This article describes how the U.S. Postal Service is effectively used for drug trafficking.
www.amu.apus.edu