USB U3 - the device that lies.
U3 USB devices sound like a great idea - a device that will run particular software when you plug it into a computer.
How does it achieve this?
Wisely recognising that most companies disable autorun on USB storage devices, because of the security risks, the framers of the U3 standard chose to create a device format that comes as a USB storage device, but claims to be a CD-ROM or DVD-ROM drive, so that it can auto-execute the U3 Launchpad, which is what opens all the various U3 applications.
So, if you want to stop automatic execution of applications on USB storage devices such as thumb-drives, you'll need to also disable autorun on CD/DVD drives as well.