It is kind of hard to classify bandwagoning...I think if you act like it means something "personal" to you that they won, or maybe that you were "some part of it", that you are clearly frontrunning. Obviously varying degrees of arrogance make it more cut and dried. Ironically the reason most people would not frontrun for the Heat was Lebron and Bosh frontrunning and Lebron's arrogance... Casual fandom is fine, especially now in a modern era where it is more about players anyway, but I think any serious rooting you have to be decided on coming into the postseason.