Was on a GTW 777 on Saturday and we had 2 Captains and 2 First Officers. It could have been for training, but I found myself wondering if there was some testing going on, as training a full flight crew is a bit unusual.
MCO by any chance? Its a 3 crew flight in the winter, 1 Capt 2 FOs. On sat the pilots were just having their annual route check, hence the extra Captain.