As mentioned during the BlizzCon Q&A, Blizzard themselves do not determine the amount of Collectors Edition that are printed. Information from pre-orders at retailers are sent back to Blizzard, where they then do a fulfillment in terms of the amount of boxes that are manufactured. Most retailers have a pre-order cut off date in terms of guaranteeing the order since Blizzard needs enough lead time from a logistical point of view. Note that some retailers periodically take pre-orders again when someone happened to cancel their pre-order at the last moment (Walmart did this for the Diablo III Collectors Edition).
Note: Right now for those who digitally pre-ordered, there are Battle.net related licensing issues associated with this where many peoples accounts are being flagged as the Starter Edition (only on the Battle.net web site which prevents many from posting on the site; this doesn’t seem to be affecting peoples live server access except for the 72 hour period of being unable to access the auction houses). I’m also having this issue since I did pre-order a Digital Deluxe for my main account.
