When I worked for Northern Telecom in California we had a young lady that had a thing for a guy in the Belville, Ontario plant. She wanted to send him some wine from Napa Valley and, being kinda cheap, sent it via company mail and marked the box "Documentation."

The box was put on the company truck that went to all the North America locations. When the truck crossed the border into Canada the trailer was inspected and one of the boxes gurgled when shook. The truck was seized but finally returned after the company paid a $10,000 fine. Pretty expensive stamp.