This is neat, but it only works if your setup is simple enough to be usable by a random thief so that they can get an Internet connection ready so that the machine can phone home. Were someone to steal my laptop and boot it, they would reach a tty login prompt in a dvorak layout, and playing around in grub would also lead to an LFS install with a patched agetty greeting them in lolcat. (My LFS was just for fun, so I did silly stuff with it.)

In other words, they would probably just wipe the computer and install Windows, and I wouldn't hear about the machine. I guess I could have a Windows install ready with a guest account and sneaky tracking software just for the benefit of an hypothetical thief, but it doesn't seem worth the effort.