The only thing that seems to consistently work for me is disabling my internet connection. Freedom (http://macfreedom.com/ http://macfreedom.com/) is what I've

The only thing that seems to consistently work for me is disabling my internet connection. Freedom (http://macfreedom.com/ http://macfreedom.com/) is what I've used. Apparently it costs $10 now, but also works on both Windows and OS X. With linux, I expect it would be fairly simple to write a script that did the same thing, though I don't know how it would get enforced.