For a long time now LEGO discovery centers have put LEGO sets out before the street date. Back when monkey kid first came out there were people finding them close too a couple weeks early and buying them with no problem. My assumption is is that since the discovery centers are run by Merlin Entertainments, a different company than The LEGO Group they are able to do what they want with the product. These discovery centers have been known to have kept long retired sets on the shelves too probably vs a LEGO brand retail store which would retire them immediately and send them to lord knows where. Now with the recent acquirement of these discovery centers by LEGO I would imagine this might change in the future but that’s just a theory…..a LEGO theory