True! Or simply "delete" the hosting (NOT the domain) in the control panel - no lag to disconnect, and only a "smallish" lag upon reinstatement.
"We have now deactivated http://www.deadbeatclient.com/!
Within a few minutes it will give a "bad_httpd_conf" error, and within a day or so it won't resolve at all in your browser.
If you'd like to re-add service, just come back to this page!
The Happy DreamHost Web Service Deactivating Robot!"
.. I think that's the way to go!