I've heard some people going on about fans jumping on board the bandwagon. I'm sure I speak for plenty of Red Sox fans when I say that, given that the Red Sox are out of the post season, the Phillies are best representing our interests at this time! That's not jumping on a bandwagon, that is just natural to support the team who faces our arch rival.
With that said, I have come across many a fan of this club or that (*ahem* Yankees) who have jumped onto their bandwagon simply because they have a good winning record this year, or because they are winning today. They have no allegiance to place (they're not from NYC (but even if they were they could be a Mets fan - there are healthy alternatives

)), they have no history, no experience with the club. They follow because they want to follow the winning record of the day. That kind of bandwagon stuff allegiance is pathetic to say the least and is completely different from fans choosing a team to root for in a particular contest.
I love baseball and enjoy watching games. Pro games, kid games, AAA, whatever. When do watch I often have a tug one way or the other to root for this team over that team. That's quite natural. That's not bandwagon. As a kid I could see the lights of Fenway every night from my bedroom window. Fenway was a second home in the wooden unassigned $3 bleacher / Yaz, Fisk & Evans era (Fisk lived in my town and I met him when he was chilling with his kids in front of his house - I actually tossed a ball to him that strayed onto the sidewalk as I passed by). So in spite of all that deep-seeded Red Sox love, I have no problem cheering on the team that plays locally, the Seattle Mariners, nor do I have a problem picking a side for this World Series. Cheering on the Phillies or Mariners, giving them that case-specific fan support would never eclipse the genetic & experienced passion for my team, the Red Sox. A love for the game of baseball permits a relationship with all the teams, for better or for worse. (I even have a relationship with the Yankees - one of loathing!)
So again, the Phillies are representing RSN in the World Series from my point of view.
"I support the Red Sox and anyone who beats the Yankees."
Standing orders.
Go Pedro!
(for tonight ...)