Drums aren't allowed into the Stadium as they are a musical instrument. We haven't needed drums to create an atmosphere in the past so why would we need them now?
Crowd sizes aren't that flash and haven't been for a long while. Everyone knows we have to get bigger crowds and do it consistently. There is a saying that if you do what you've always done you'll get what you've always got. It works in many other A league stadiums and other football venues worldwide. Could we do better here in Wellington?
A drum in the Yellow Fever Zone isn't going to improve crowd sizes. People who are likely to come to games simply because of the Fever and the atmosphere are already attending matches. Crowd sizes can improve for other reasons, but putting a drum in the Fever Zone is going to get a negligible amount of extra people coming to games.
Besides, we tend to go for the English style of supporting, where one starts a chant and it either catches on or they get giggled at for singing on their own. As opposed to the Eastern European style with drums and flares, like the RBB do. Drums just aren't our style.