UPDATE: WWE reportedly promoted the "CM Punk vs. a member of The Shield on SmackDown" on last Monday's RAW because at around 10PM on Monday, Vince McMahon had yet to come to a decision on which of the three members of The Shield would be the best opponent for Punk.
ORIGINAL: As might be expected, Vince McMahon and Triple H are reportedly the only real key decision makers in terms of power within WWE. A new report says that plans for SmackDown are made on late Monday afternoon once RAW is set, and that the two don't begin to start talking about the Friday show until then.
Around 6 PM on Monday, McMahon will ask the writing team for a main event on SmackDown so that it can be promoted on RAW and at that point, writers begin trying to come up with ideas for a big, promotable match. This is said to be the reason that SmackDown and Main Event matches which are announced on RAW often change. This is also just another example of no long-term booking and very late creative changes on a weekly basis.