Thanks AA [missed MIA connection]
Also Jordyn, placing GAs in the position of whether policies should be broken in individual circumstances because passengers may or may not come creates an opportunity for discrimination and/or other abuse.
(You also have no knowledge of whether things like the need to get another airplane to that gate played a role here, but are nonetheless asserting your superior judgment based on the fact you've seen a very small airline put people on a plane close to departure.)