I believe online retailers will keep proof of purchase themself and send to those who payed for it at release. I also believe that it will be sent as soon as they are allowed which is either day before or on release. So the only thing you can really blame if you don't get the CE within those 5 days is the post service they use. As mentioned the 5 day period for the code is only a grace period of which you can still play without attaching the real game code. So basicly the 3 day headstart code is a 3 day headstart + 5 days of playtime without adding the real CE. You can actually use that time to try out the game (if you haven't already) and decide if you want to keep the CE or sell it.