Shutdown pauses when others are connected

[Homer]

Kubuntu 10.04

I've noticed a new "feature" recently.  If I ssh into machine "B" from
machine "A" and then walk over to machine "B" and execute a shutdown,
I get a message notifying me another person is logged in from machine
"A."  The message asks if the shutdown should be canceled or
continued.  I'd like to set the default to shutdown with no
consideration of other connections.  How can I accomplish this?