Ah ok that's evidence enough not to do it. Ever want to do something and you know it's wrong but you don't know WHY it's wrong and it's hard to find evidence to show it is? That's where I was at. I wanted to set the homepage canonical to the vanity but I knew it treated it like a 301 redirect. My only impulse to do it was that the vanity URLs were appearing in search. Ok so I won't do that.
The only other question is since Google is putting some of the vanity URLs in search and some of the homepage urls in search, is there any way to keep it consistent? It seems like there isn't since Google is disregarding the canonical (which is all to the current homepage and not the vanity) sometimes in replace of the vanity.