Rock Band release date broken in UK?

So I was winding down a very busy day today of numerous errands that in the end took me to the Costco in Croydon, south of London. Over my shoulder I noticed a stack of Rock Band 4 Band-In-a-Box bundles for sale for I think £149.99, might have been £139.99. I thought to myself, "Huh, I didn't realize Rock Band 4 had even been released yet." It's been a pretty busy week for me so it's not unheard of that I would have missed it. But it kinda gnawed at me and when I got home I checked the release date and lo and behold, it doesn't come out until Tuesday, October 6th. I really regret not snapping a photo at the time but there you have it. Want Rock Band 4 a few days early? Have a Costco membership? Head over to Croydon and treat yo'self. 

I am sure this is an honest mistake by the fine staff there at Costco and it may very well be corrected before Tuesday, but I can deliver a first hand account that Rock Band is on sale right now at the Croydon Costco.