Another angle on blue umbrella..
This man in the blue tie is seated, I believe, in the seat where Durham (in a previously posted video) very purposefully placed the blue umbrella. Durham looked at his empty seat, then placed the umbrella on the empty reserved seat and checked again, it appeared, its relationship to his own seat. It looked deliberate and, franky, obvious.
https://pbs.twimg.com/media/FzJymfSX0AchYVI?format=jpg&name=large
(Man in blue tie in the seat, I believe, was where Durham purposefully placed the Blue Umbrella.)