I've mentioned before, but at work, we used to have to hire a customs agent, a third party, to get moderate numbers of boxes of research publications across the Canadian border, which used to be a fairly friendly crossing. It is partly the bureaucratic red tape that stalls innocuous shipments. One always suspects corruption in the pipeline. At the least, a second revenue stream is created by necessitating customs brokers. I think of Canada and the U.S. as relatively open societies as relates to customs. I'd have more caution with some European countries, and even more in other regions. When I donated pipes and blends to the military people in Afghanistan, to an Army Post Office (APO), I had to fill out customs forms, and I was a little surprised when the box actually arrived. Customs often means trouble. It is either effortless or hopeless, a flip of the coin.