I have had questions myself about what it really means to be a fan. Like my friend once told me I take the idea too seriously and go to extremes about it. Which I do agree because I blow a lot of money in collecting merchandise from them and buying cd's and what not. But is it really extreme?
So as Mamiisthebest has said, there is generally the good fans and the bad fans.
To me the good fans are the ones who show the most dedication by supporting the group whether it be in the form of purchasing albums, merch, or maybe even gifts that the members really appreciate! Now I don't believe Scandal should be the only thing you ever listen to because there is only so many times you can listen to their music and you will eventually get bored. That may just be me being a bad fan, but regardless, I like to cherish the music they make as much as I can.
Bad fans of course take advantage of what they offer by pirating and/or being rather disrespectful to them whether it is forcing an autograph or a picture out of them. I think the biggest "sin" they can really commit is chasing people away from Scandal and try to keep them for themselves. What drives the biggest groups/bands in the world is mostly big,supporting fan base. And with more support, Scandal will live longer.