I have a consistent problem where new volumes (or volume pointers) will be created for the same drive. See attached. "ELEMENTS" is a 300GB USB drive. "1TB-DSS" is a brand new 1TB USB drive. I properly dismount them every time before pulling the USB plug, but for some reason, I'll have "ELEMENTS" only, and then a new "ELEMENTS 1" will show up.
As you can see from the screenshot, each volume "directory" doesn't have the same files, which is the real source of my problem. For example, when I bought "1TB-DSS", I added "Zipped" and "pics". Later on, I added "dsstaowin7-parallels" and other directories without realizing that OS X was now seeing these under "1TB-DSS 1" instead of just "1TB-DSS".
This problem has persisted since I had Snow Leopard, and now I'm on Lion, with no change in behavior. It happens on multiple USB drives too as you can see.