I probably should just do a normal "comment" on Dave's entry before, but I thought it's worth it's own ErrataSec blog entry.
DON'T affix a sticker saying "NOT A BOMB" on devices you take through airport security. It's against the rules, you will get into trouble. (...and no, that's not a silly rule, there are good reasons why it's bad).
Soon after 9/11, ISS had this marketing campaign and gave out T-shirts that said on the front "a different kind of THREAT", and on the back "needs a different kind of SOLUTION". The word THREAT was huge across the front.
So of course, I had to see if I would get into trouble, and wore it to the airport on my next business trip. I wore it on every business trip for the next year. I didn't get into trouble, but the TSA people would usually make a comment about it (not a comment saying I shouldn't wear it, more of a comment reflecting the fact that they noticed it).