I had never heard of anything like that either, until I read the article. It makes sense though. If there isn't anyone to fly the plane...it isn't going anywhere. True, the hijacker might be able to fly, but that isn't likely. (Remember the 9/11 hijackers could fly but demonstrated no ability to take off or land)

I suppose that all things considered, it's best for the pilots to evacuate if they can. It's not like the Captain is really going to be able to do anything to "protect" anyone anyway.