I think you will need to reprovision the drive to be EPO managed, then you can take control over the various settings, like the AV scanning.
The USB drives are not centrally managed at all. Can a stand-alone be provisioned? We also do not have administrative rights to our laptops so if this is something that would require administrative action, we are out of luck. As I said, these were purchased to be stand-alone and the anti-virus on them is irritating, problematic and redundant.