Hi level security is something you have to see (or preferably not see) to believe.  When George Bush, Sr. was president, he gave a speech at the Boeing Aircraft Company museum up in Seattle, Washington.  He arrived, gave a short speech, and then departed.  After his speech, they kept the entire staff there for two hours, and nobody was allowed to leave..  Nobody was allowed to see where he went, or how he left.  We arrived shortly thereafter, to tour the museum.  The staff was still shaking.  A senior Boeing vice president, of which there are many, decided at the last minute to attend his speech, but they would not let him in because he was not on the approved list.

Those people are NOT playing around.