Disabling yellow shield

I am in a situation where users cannot be notified or have any interaction
with software installation interfaces. We use SMS to push out microsoft
updates, and SMS has a feature to supress all user notification and
interaction. We are configuring WSUS to mitigate any security updates on
machines which failed the SMS pushes. Although we can configure only admins
to be notified of updates that have been installed, we have ordinary users
who must both be admins (at least until we can successfully mitigate each
application's admin requirements on a case by case basis) on their own
machines and also not be notified of pending updates and reboots.

Is there a supported or unsupported hack to the registry or group policy
which can be used to PREVENT ALL USER INTERACTION?

I appreciate any help you can provide...