Hey pervs. Fancy recording all the hotties you meet with a hidden camera stuck inside a baseball cap? Here ya go. And it only costs £645.00 ($1275). But who can argue with the price when you get a 720x480 image stored on a 4GB SD card. Too bad the battery life's only 60 minutes, or you could really get some good material.
For non-prurient uses, stuff like this could be handy if you want to catch an unscrupulous mechanic or some store clerk being an ass to you. Having evidence of wrongdoing always works—unless there are laws about videotaping people who don't know about it.