or to be more precise, it used to, but doesn't any more. M:S that is.
However, if you are a single rider, it never hurts to hold up one (nice) finger politely as you get toward the front of the line. I've been pulled out as a single rider lots of times on rides that don't have a single rider line. You won't shave off the whole wait, but it can knock off like 2 or 3 minutes.