A friend had already boarded. They announced the plane was overweight. Without asking for volunteers, they took my friend off the plane because she was last to board. They did not first ask for volunteers, and they gave her a voucher for far less than the DBC amount.

Was this a DBC situation? Presumably the airline could have added fuel, the overweight situation was a result of last minute boarding of passengers from another (delayed) flight. (I'm assuming that when my friend was shifted to the new flight her reservation was changed to that flight; I'm not asking for opinions re whether she had a reservation, but whether removal of a passenger from a flight due to an overweight situation requires payment of DBC.)