I am more worried about some dedicated reddit, or 4chan user getting angry than the feds. I'm weird with this because when I write posts I wait 2 minutes, and think how would feds interpret my posts, and is it worth posting that.
I will most likely make a mistake with my anonymity one day, but to have alts increase anonymity wouldn't you have to be good at changing your writing style?
There is no such thing as perfect anonymity, but it is a small and simple step which makes it harder to build a profile of you. If you slip up, the amount of informstion that can be gleaned is more limited.