In modern Windows environments, you rarely need to walk to a user's desk. You can force a gpupdate remotely using PowerShell or the Group Policy Management Console (GPMC).

Or use psexec (from Sysinternals):

You have disabled USB storage access via GPO, but a user can still plug in their USB drive.

The command handles modifications for both the computer and the currently logged-in user. The basic syntax is:

gpupdate command