Absolutely impossible! No one in their right mind would keep Hu in the dark for this important moment. Everyone knows that the test flight was more of a political move than technical. As the political leader of the nation, Hu would be the one who had to decide when, where and how the public test flight would take place. I wouldn't be surprised if they had multiple meetings on this. So to say Hu had no idea of the public test flight is like saying Hu had no idea of a national parade in Beijing on October 1, 2009. Politically two event have the same goal although the magnitude might be a little different. both would need the approval of Hu.
the timing the event suggests its tie to Hu's visit to the US. This means the public showing is an important strategic move. I don't think Hu forget about something this important.
Plus, a sudden change of the level of security around the airfield suggest a major change in the policies, which definitely needs approval from the top. No one would risk treason by leaking national secret (the J-20 tes flight, which proves the existence of the stealth fighter project) to the world.
I beg to differ about the timing of flight being politically motivated. The progress of JXX prototype has been followed closely on SDF for the past year, we are more or less informed about critical stages of development such as final assembly in April, ground testing from October, lower speed taxiing from November & higher speed in late December etc. Then the maiden flight occurred in due process, apart from the weather drama on 7th Jan. I do believe the timing of flight was a technical matter instead of a political one, since nobody can shorten nor lengthen the timeframes for previous steps, though one may attach some cultural/sentimental importance to the specific 11/01/11 date.
Therefore Hu means what he says, the maiden flight of J20 was indeed planned beforehand, based on the actual progress of the project more than anything else.
Alternatively if they decided to postpone the flight due to Gate'd visit, that would be truly politically motivated.
But of course the assumption that Hu didn't know about the flight is utterly ludicrous even logically fallible, how do they know if Hu was simply surprised by the question itself other than the content of it?