I'm not familiar with the design of the car, particularly the interfaces with the electricity and hydrogen. But I do know three things:
First of all, you don't need a direct connection with mains power to ignite a contained supply of hydrogen. A single spark or arc will do it, and we're all aware how easily that happens when inserting live cords into anything. (Actually that's not quite true; for good reason home and office electrical plugs usually go into the current, but the effect at the junction is the same whether you're plugging a live wire into a dead source, or vice versa.) There was most definitely a good deal of risk of fire, which remains one of the top reasons why hydrogen cars are not in mass production already. Furthermore, if President Bush had succeeded in touching a live wire to a hydrogen outlet, even if no fire had occurred somebody would have realized what had happened, and a scandal would have erupted. Heads would have rolled, maybe there would have been lawsuits too. Ford is in a bad way right now and doesn't need to add to its troubles with a news cycle of "Ford car of future nearly kills president today."
Second of all, Alan Mulally himself is a pretty decent guy. He was CEO of Boeing Commercial Airplanes out here in Seattle, and had been with Boeing for his entire career before going to Ford. He is an engineer through and through, and, as an engineer myself, I take quite seriously the urgency with which Mulally recognized the danger and intervened--against protocol--to prevent any contact from occurring between the power cord and the hydrogen supply. Good engineers know their shit, and if you ever see one get nervous and agitated while putting on a tech display of his own toys, then you had best make your time.
Third, Mulally was there with his Ford delegation because Ford wanted to build some White House support for their hydrogen hybrid concept. Effectively, Bush was there at Mulally's request--not the other way around. If this incident had been intended to attack the president's intelligence, it would have been in direct contradiction with the business aim of the demonstration. That is more than simply unlikely. That is implausible!
Face it, Republigoons! Your president is not only the most incompetent in this nation's history...he is also the dumbest.