I have recreated the problem...
Host is Windows 7 Ultimate, 64-bit. VMware Workstation is NOT installed. USB Flash Drive is inserted into a USB port and is seen by the host.
Install VMware Workstation 9.0.0. USB Flash Drive is inserted into a USB port and is NOT seen by the host. Start VMware Workstation. All entries in the VM menu are greyed out. Start a virtual machine (Windows 8 64-bit). VM menu items are active the USB flash drive is listed as NOT connected. Connect USB flash drive to the virtual machine and it is seen by the virtual machine. Disconnect the USB flash drive from the virtual machine and it is now seen by the host.
Install VMware Workstation 9.0.1 and repeat the experiment, exactly the same results.