I can see a smart-ass TSA agent seeing your kindle and nonchalantly mark it with his permanent red marker, then in one fluid "kthxbye" motion give it back to you and move on to the next person in line.
You'll complain but they'll just reply back with Amazon's marketing line "It's just like paper!"
Since your a new user I'll let you know that your being down voted because your comment doesn't actually add anything to the conversation, a comment of agreement should be replaced by, at most, an up vote of the parent. I know it cliche but please read. The guidelines, http://ycombinator.com/newsguidelines.html , otherwise you'll be hell banned very quickly.
Edit: I've lost my editing power so I guess it'll stay that way.