There is a video of this small craft and after watching it I can see no obvious reason to park the ship and take a look.
If these guys had money for fuel to "go fish" then they had enough money for:
A distress Flag at the very minimum.
A small piece of Mirror.
A road flare.
Maybe even some Sea Dye.
They do not even seem to have OARS.
How tough would it have been to tie a shirt to an OAR
and use that as a distress Flag?

As others have stated there are a few reasons why a ship would not want to stop without actual proof of distress, Security is only one of them.
The Capt. at the time has assisted other vessels/crews.

Darwin sucks but does work.