Yea, this thing's just asking for trouble. I don't actually know how I've managed to go this long without absolutely wrecking somebody's day with this thing. To be honest, I don't actually remember how it came to be that I have one of these, but hey, isn't that how all the best stories start?
Anyways, open this up, stick it right against the leading edge of a tire, and if the driver pulls forward, they're going to get a flat tire. Pretty straight forward.
Disclaimer: You buy this, and it's your deal. The backside of the device states "THIS DEVICE IS ONLY FOR USE BY LAW ENFORCEMENT OFFICERS" so keep that in mind if you're thinking about using this on a vehicle that doesn't belong to you. But then again, if you do feel like flattening your own tire with this, please get video and share it with me. In fact, I'd bet YouTube would be a great place to share that video.