Lets wait and see, but it could be that this is a normal procedure between changing administrations. Not unusal that Bush takes part, his experience is as important as Obamas lesson to handle something of this magnitude (not that bush has any kind of useful things to say, but you get the picture)

If something was about to happen, it would be in the next 2 weeks, so everbody, stay tuned.

COG "Continuity of Government" has to be at the forefront of security concerns during the innaugeration. With that many people, and our entire administration on hand, who goes where and in what order must be a logistical nightmare for the agent foster grants out there. Every member of the outgoing and incoming admin. probably has a set procedure they must learn and know in the event of the unthinkable. I'd love to be a fly on the wall during these briefings, if only to know just how much goes into the planning phases of this type of event.
Mind blowing.

Should not come as a surprise. Remember that Joe Biden himself made a public statement shortly before the election stating that he expected Obama to be tested within the first six months of his term.

One thing to bear in mind is that Bush expressed frustration at the outgoing Clinton regime for their lack of assistance with his incoming administration in the days surrounding his swearing in. He's said that he feels it's the duty of the outgoing administration to assist the "new guys" in any way possible or requested. It is highly possible that Obama requested this exercise to better familiarize himself with the current gameplan so he doesn't feel the need to reinvent the wheel.