I take issue with the title of this article... there is a big difference between not giving two weeks notice, and taking parting shots when you leave. If things are shaky at your existing employer, and someone wants to hire you somewhere else and is anxious for you to start, I think it's perfectly rational and understandable to want to start at the new employer immediately.

I have personally known people who had job offers extended, and then had the offers rescinded before they actually started. I think this creates further incentive to jump to a new position without two weeks' notice to your previous employer.