While drifting around the Internet tonight I came across this product. http://tinyurl.com/6f8rpn
I was very impressed with the idea on my first impression. You use the grey colour coded keys (the colour coded key only works in the corresponding coloured USB filler adapter). Now this is not the ultimate locking device because anyone can go buy the correct grey adapter key to remove the fillers, however for those terminals that undertake sensitive processing, or a public terminal, it is a great way secure against attaching unwanted devices by convience. The side benefit from an employee discpline point of view, if an employee removes the filler adapter, they cant claim they didnt know they shouldnt be attaching unapproved USB devices.
The biggest downfall I see with this devices is that most keyboards and mice are now USB. So you obviously cant use this to fill those ports. What is to stop someone pulling the keyboard USB cord, plugging in a USB hub, and then plugging the keyboard into this. Therefore to make this product useful it needs to be supported by another adapter. This could be a two-way locking adapter so you can lock a USB device/cord into a port and it cant be unplugged easily (which stop office theives borrowing your keyboard/mouse/webcam when theirs break). In the public spaces this would also protect against the hardware based keylogging adapters. If anyone knows of such an adapter please let me know.