"Life is too short to safely withdraw the USB device."

                                                  *Unknown Author*

Zazzle already sells its USB with this text :)[http://www.zazzle.co.uk]

Many of us experienced the feeling, when we were in rush and need to remove the USB flash drive from computer. But then it appears - System cannot unmount disk and it can be dangerous. Why is that?

Computer tries to optimize its performance, works as much on system memory - the one that is the fastest in writing and reading data. On the slower memory (hard disk) writes only occasionally. System thus operates with cache for each disc. Although outwardly it may seem that something is inscribed on a portable drive, in fact, the computer holds in the buffer information about what will be needed and where to write.
When removing a disc using the recommended method to remove it from the computer, the system sends a command (ie. "Flush") to ensure that all temporary data cache has been registered on a portable drive. Only then is it possible to guarantee that they are written to disk all the data you want to store there.

But there is a solution in newer versions of Windows (7 and up) - if you set in Settings - HW - USB - "Quick remove".
After that you can safely remove your USB stick anytime without risk.

Hope it helped you!! :)