What makes you think they are bandwagon fans? The Cardinals have a strong fanbase and they are nationwide.
They are arguably among MLB's best fans, in terms of knowledgeability and of sticking with the team (for the most part) when less-than-successful times come, as well as in winning seasons.
That having been said though, I'm really hoping we don't get a large opposition turn-out tomorrow (which seems possible with so many here unable to go because of the timing) - I remember them turning out big-time back in the RFK days.