Originally Posted by
1Newflyer
Conveniently you choose to forget about the kids : "My daughters walked on the plane in front of me with their carry-ons" And this sentence was in front of the one you present as evidence. Shame on you. Three passengers may have 6 pieces.
unfortunately, your reasoning is more complex than what is offered by OP - only information is children had 1 bag each and father had 4, and thus we can infer the father had more than permitted based on what is known.
The logic of 2 bags each requires two further assumptions, and on principle of simplest reasoning first ( otherwise known as Occam’s Razor) cannot agree with your assessment.