[glad I decided to leave when I did]
1) First thing that will happen, motels will become lodges for locals (not bad).
Or sell up and add to the overpriced mansion epidemic that is auckland.
2) Visitors will stay in Hamilton and drive up to their concerts adding to the traffic.
3) Visitors will rent camper vans (probably not from auckland).
4) Visitors will use Couch Surfing services.
5) Promoters will move their concerts to Hamilton (fastest growing city in NZ, also third largest and closing in on Wellington FAST).
6) Backpacker accommodation will close, making it even more difficult and expensive for locals to stop in auckland. Poor tourists won't be able to go there - not a bad thing though, they get to see the best of nz and avoid the worst.