It's supose to be a project of Creative Commons licensed sounds, why don't you let unregistered users download them?
At least for some consideration you should not ban the bugmenot users...
I think it makes me people think more about contributing by doing this. This is not a spamming kind of site. And its a small thing to do for Free Sound. I don't think there's any important bits of information you need to enter in.
Its also important because I believe it forces people to read the license if I remember correctly.
I don't think I'd even be on these forums, let alone upload sounds and get sweet setups from game designers if everyone could download the samples without registering. The only reason I signed up was because of a single sound I wanted to download, then this whole world of recording and specialized audio engineering opened up.
Forcing people to read the license is a plus, also it helps us track downloads and behavior of indivudual users, as opposed to just anonymous IPs that could be many adresses for one person or many people with one address...