Things can and do in fact change after the race begins. In fact, things can totally flip around during a single commercial break . . .
"Controversy surrounded the final leg of the race: when Rob & Amber and Uchenna & Joyce arrived at the airport in San Juan, they were both sold tickets for a flight leaving later than one whose gate was about to close. While Rob & Amber managed to get on this earlier departing flight, Uchenna & Joyce were shown through the gate as the boarding corridor between the gate exitway and airplane began to shut. After a commercial break, the boarding corridor reopened to the gate to pick up Uchenna and Joyce. No explanation was given as to why the gate reopened, which has led to widespread speculation about intervention by the production staff. In the "Revisiting the Race" special feature on the Season 7 DVD, Uchenna, Rob, and Host Phil Keoghan deny the accusations of intervention by the production crew. Uchenna describes his experience with finding the same airline agent at the gate who had previously informed him that there was no earlier available flight. Rob describes Uchenna running around frantically trying to get onto the flight, which the final edited version of the show does not portray. Phil cites the fact that the decision to reopen the door rested solely with the pilot, and that intervention by the production crew would have resulted in someone leaking such information out."