Admin password needed for Power User

I have a lab of 60 machines all ghosted with the same image. All bought at the same time. I have a student profile that is a power user on all but about 8 machines we can plug in the same exact usb drive and it allows us to use it. On about 8 I get the box requiring an admin login with password. I don’t want to make student an administrator. Is there a workaround?