A guy named Brad gets peeved about how his luggage always is getting searched when he flies. So he creates this packing tape
so, as he says, "Now, when they open my luggage, they will have to literally slice the 4th amendment in half in order to do this." There's lots of interesting discussion in the comments on his post about whether airline luggage searches are unconstitutional or not, but if you like this idea, you can buy the tape at the Electronic Frontier Foundation store.
(Thanks to BoingBoing for the pointer.)