So in the first Pirates of the Caribbean, The Curse of the Black Pearl, when Jack Sparrow first arrives at the port, the man asks him for a schilling and his name in order to "tie up his boat" in the dock. Jack Sparrow gives him 3 schillings instead in hopes for remaining nameless. As Jack Sparrow walks away, the man calls him "Mr. Smith". Also, later when he is talking to the two guards at the boat, just before Elizabeth Swan falls from the ledge into the water, the guards ask him his name and he replies "Smith". Is there any significance in this in the fact that he is referenced to as and references himself as Smith, since the first mate that he recruits for his quest is Arabella Smith, the daughter of the infamous pirate Laura Smith? Or is this just a mere coincidence?
I'm not sure if it has some special significance in this particular instance, but "Smith" is one of the most common surnames in the US, perhaps even the most common. So when someone wants to pick a pseudonym to mask their true identity, it's a typical choice. And for some reason, "Smith" has acquired this reputation more than any other common surname, so you'll frequently see it used for that purpose in TV and movies.