How to create a user who can't make wireless connections

Is there a way to create a user who does not have permission to initiate or create a wireless/ethernet/modem connection?

In System > Administration > Users and Groups > [username] > Advanced Settings > User Privileges, it appears that you are able to control whether a new user can have permission to "Connect to wireless and ethernet networks" or not. The setting doesn't work. To Test: Create a 'Desktop User' without this permission. Log out. Log back in as new user, and you will still be able to use the network manager just as an Admin could. This is apparently an artifact of the transition from old style unix groups to policykit and is reported as a bug here:

https://bugs.launchpad.net/ubuntu/+source/gnome-system-tools/+bug/326135

I have tried in Ubuntu 10.4 and an updated 10.10 beta.

According to the bug report, these options change the groups the user is a member of, but that is simply not respected by Network Manager. Anyone have any advice on how to either (1) create a user whose privilege limitations Network Manager will respect or (2) make Network Manager respect Unix group membership?

If this is not the place to ask this, I'll happily go elsewhere. I post it here since it results from the above bug which is posted here in gnome-system-tools.