They do this a lot in Europe with BD. In the past few years we got the following a long time before the US release:
The Rock Air Force One Starship Troopers Crimson Tide Starsky & Hutch (glitched subtitles though and Disney-BV not WB) The Island
Then we still have not got these US titles:
Cast Away Patton Die Hard3 Big Trouble In Little China
A lot of it is that sometimes a different studio owns the international BD rights such as DH3 is not Fox but Disney-BV then other times I thinks its down to licensing music on the soundtrack & or actor contracts for global releases. As BD is pretty much a global standard you would think that nowadays they would give everything a std release date but they also have to put additional languages on the EU BD's. Gremlins 1 & 2 were yanked at the last minute and this year they had Charlies Angels1 + 2 movies for a July release but pulled those late in the day as well as several others.
Patton is available in most of Europe but not the UK. There are many other titles not available in Europe, none of which have studio rights problems, such as The Robe, The Sand Pebbles, South Pacific, Adventures of Robin Hood, Battle of the Bulge and 7th Voyage of Sinbad,
Amazon.fr , thats the french amazon, have this listed for October 7 !!!!! Thats 2 weeks earlier than uk.They even have the original poster as the cover art.Ive preordered it,The original coverart seals the deal for me.