To be brutally honest, I doubt any current president will be able to attend Champs. Here's my reasoning:

A. It's open to the general public. This makes security an even larger nightmare.
B. Teams enter and exit with toolcrates constantly. This creates a security environment that is inoperable for a president. It would be disturbingly easy to smuggle a firearm into a FRC competition, hence the lack of likely hood of his attending.
C. We're not big enough. This is the president we're talking about here, folks. This is the most powerful man in the world. We aren't big enough yet. We're close, but this is the man who single-handedly packs millions for speeches.