The last time we see Elizabeth Swann (because c’mon she was a Pirate King, no way she was giving up her last name, lets be reasonable now, if anything she was hyphenating her last name) she had a kid.
Now lets imagine pregnant Elizabeth, all alone. She keeps up the pirating, its expected with her now being one of the Brethren. Imagine Elizabeth hiding her pregnancy, because its hard enough getting a crew to sail under a woman, but one whose with child?
Jack figures it out first and freaking panics. Eventually the Pearl’s crew figure it out, and they they vary from freaked out don’t make any sudden movements to freaked out and wondering who the father is (most are sure it’s Will, though there are very hushed whispers that suggest Norrington or Jack).
Imagine the pirates freaking terrified to meet the small Swann-Turner. Because babies are innocent and fragile, things pirates just aren’t. Ragetti and Pintel are surprisingly good with the little one, and when Gibbs shows up he always has a story.
Jack pretends to not care, but its one of the most transparent lies he’s ever told.
Elizabeth insists on using the phrase “Uncle Hector” when referring to Barbossa. He allows it as long as there are no other crews are around to hear.
Imagine sailors and pirates far and wide hearing the whispered warnings of a child born to the captain of the Flying Dutchman and a Pirate King. Of warnings whispered about the terrible fate of anyone who would dare hurt such a child.
Imagine Barbossa slaying his enemies at sea, and whispering into their ears updates on the child’s life to pass along to the father, claiming the messages would grant them faster passage.
Jack doing the same when he is forced to kill.
Imagine Will on the decks of the Dutchman having a freaking panic attack at least once a week for ten years hearing about his child being raised by pirates.