My take on this would be how the client dev code was written.
Look at vbscript for example. Using a WMI connection, Win32_LogicalDisk sees a USB drive in a similar way but with important exceptions like MediaType, Description, etc...
If the dev code for the client is written to examine "Local Fixed Disk" then USB would not be scanned. USB (in WMI terms) is seen as Removable Disk. CD-ROM as CD-ROM Disc and so on. (Funny how CD is seen as DISC and USB is seen as DISK. I guess CD is seen as optical...). Even a Daemon generated virtual drive is seen as a CD-ROM Disc.
Anyway, although not tested on my end, I would go with a "NO" on USB scanning.
M