Default profile - permissions too high

Hi All,

Is it possible to limit access to what people logged in under the default
profile can do?

Scenario: We have a Windows XP network. Users have determined that if they
start logging on then pull the LAN cable when the "loading personal settings"
prompt is on-screen they get a default profile with no GPO restrictions.

Is there any way to deny logon to a machine when it cannot load the users
network based profile? Or if not, at least restrict it. I have set cached
logons to zero but because the LAN cable is connected when logon is initiated
this security feature is bypassed.

Thanks in advance