Stupid people...if it said a delay due to something that is likely to ihibit success, I would accept it. A delay due to something that can easily be fixed within a week should hardly be a decider whether someone stays in a spec stock or not. The bet here is on the flow results, i.e. whether they can get profitable oil out of the ground, not how fast they can do it.
The only other reasons I can think of are short termers who hedged everything on getting an announcement this week, or people expecting a drop on any announcement and trying to beat others to the chase so they can buy in lower.