I think Noble's point is they are still a lesser known indie band. He's trying to avoid putting the bands the general public knows in the poll. An example for songs that are already in RBN: Higher by Creed, the Third Eye Blind songs, Paralyzer by Finger Eleven, etc.
Of course, where we draw the line for indie bands is hard. Yes, Bang Camaro is known by the RB population in general. Amberian Dawn has become popular with RBN users. Fine. But how do we judge an indie band is "too popular" for this poll?
And, FWIW, I bet I could go up to some of the casual Rock Band players I know, ask them what they think of Bang Camaro, and most likely they would say "Who's that?" until I tell them that they're the band who made Pleasure (Pleasure) on RB1 and Night Lies on RB2. These same casual players also likely do NOT know who Amberian Dawn is, because they find RBN intimidating and less interesting, because there's tons of music, mostly by bands they may not know.