I used to pick up 4 people at once (like a car pool) out of the upper east side aoartment buildings and take them down the FDR to the last exit before the tip of the island. They would get out and walk to their buildings from there.
I would get back on the FDR empty and go north to 14th St, where there's room to move and there are plenty of fares.
Believe it or not, there just aren't enough fares going north from the WTC or Wall St. that time of day to make getting stuck in the traffic around there worthwhile.
I believe it just didn't understand the reason. thanx