I guess I've just never left it in the primary. Fifteen years of brewing and when I started with Charlie's book, it just said to rack to a secondary and I did and have every since, lol.
I figure if it's not broke, don't fix it. Over those years I can say that I've only had possibly 2 batches that have had something wrong with them, bacteria wise.
I've read studies over the years that said that sitting on yeast too long imparts off flavors to the beer. And then I've also read about plenty of people like in this thread who have good luck with it. So ... I guess, do it one time and if it works for you with, relax, don't worry and have a homebrew.