Wow. I'd think that transporting any kind of marijuana across state lines as a seriously illegal act. If so it strikes me as incredibly risky and ill advised. Why would so many people risk so much for pot?
I met an oil guy from Texas who had come into the state on business and had purchased some pot for himself. Due to the nature of his business he couldn't actually smoke any.. he just wanted to buy some for the novelty, to give away to others.
Your point stands however-- draconian anti-cannabis laws do exist, and enthusiasts will nonetheless take risks to indulge.
In my case, I never board a domestic flight without at least four bluntsworth of bud. And recently have been taking the same approach for international flights originating in the US with stops and terminus in countries with a strong tradition of rule of law and/or cannabis tolerance (ie, most of Western Europe, North and Latin America).