Lot of people are claiming that they've already got hold of Rock Band. A lot of people may now be a little disappointed. Appears the game's demo units shipped to retailers in what looked like retail packages. Seeing as some retailers aren't as bright as others, these bundles have already gone on sale across the US. Sadly for the purchasers, they're not getting everything they paid for, Harmonix stating:
These demo builds are kind of hobbled - for one the drums don't have kick pedals. Some of the demos don't have mics. And the build isn't a full-real retail version of the game. It is hobbled a bit and, obviously, the bass drum autoplays since there is no pedal that comes with the demo.
So if you start seeing eBay auctions turn up over the next week or so, do try and exercise a little restraint. Regarding "broken street date" copies for sale [Rock Band Forums]