Traveling.

Okay so I see an enormous amount of posts on here of you guys in other countries smoking, and posting pictures of your smoke spots. So, I want to know how do you guys do it? Do you somehow secretly take it on the plane?(it's a stupid question, but I wonder) Or do you just go out on a limb and try and find someone that has some on them? It has always ran across my mind whenever I've come across those posts. I'm just curious that's all, Thank you.