I personally hate Nickelbacks music, I think its boring and trite, however, they have a record contract, and have sold thousands? millions? of albums. (I dont know and dont particularly care.) They obviously do have fans, otherwise they wouldnt be touring internationally. And who, as a musician would play for a crowd who doesnt care that you are there? If they were opening for someone, well, sucks to be them, still doesnt justify having rocks thrown at his head. If they were the headliner, wtf were all those people doing there to begin with? I know I wouldnt pay the price to go see a Nickelback show to throw a rock at the motherfucker.
A side note, a friend of mine who works as a stage hand here has worked with/for Nickelback, I think she said they were decent guys (I might be wrong though, I will confirm later)
Edit for name correction, despite the fact that I still dont like the band.