All of a sudden, the cops left and so did all the taxis and shuttles without any passengers. That was also a clue.
The hotel informed us that there would be no shuttles to the conference center this morning, no shuttles to the airport, and no taxis because the President of the United States and the Vice-President were arriving.1 This requires shutting down I90 for several hours.
I decided to eat breakfast in the restaurant and wait out the disruption. (There wasn't anything interesting going on at the meeting this morning anyway.) I watched the motorcade go by on the Interstate. There were about a dozen cars lit up like Christmas trees, including an ambulance with lights flashing. Most of the lights were blue but there was a pretty mixture of yellow, red, orange, and green.
Judging by the number of angry people in the lobby, I can understand why the President and Vice-President need so much protection.
1. They are attending the opening of the Edward M. Kennedy Institute.