There's no faster way to corrupt a USB-plugged device than to simply whip it right out of the computer without going through the software disengagement process. So Apple is looking to patent a process it rather dryly refers to as "Hot Unpluggable Media Storage Device", which basically means a hot-unpluggable iPod.
The system works by allowing one to keep a device plugged into the USB port, but only actually "active" whenever you're transferring data between the device and the computer. When it's idle the USB connection will read as "disconnected", even if the device is physically plugged into the computer.
Smart. Quite smart, Mr Bond. Expect to see such a feature on the next generation of iPod.