No ones saying that YOU cant create the threads. I think a rule stating only fans of the groups should be allowed to make the thread goes a touch to far.
What I am suggesting is there should be a sensible limit on how early the thread is made.
Like some here have said, making it early causes confusion, it runs the risk of dropping from page 1 and you yourself just said sometimes you're too busy to update it when the song actually releases, meaning people who are excited to give votes on release are stymied.
What value is created by making a thread for Bop or Flop 24 hours before it's released?
And yes, others can make their own thread, but as SooYoung said, they will probably end up with their thread merged into the premature thread anyway.
