Well, those are true rumors, some people do that, some breweries do that. All it will potentially do is help you carb faster. I don't do it because I like my lagers as clear as possible and extra sediment (in yeast form) can possibly compromise that. Additionally it is an extra step, I try to avoid unnecessary steps. I'm sure others do the opposite of me, this is one of those debates where people differ but either method will get you from A to B, it's just personal preference.