Kuina and Zoro ultimately did not make a move against the strange pair of Luffy and Koby.
Although Luffy kept calling himself a pirate, neither Zoro nor Kuina could sense any pirate-like aura from him.
Along the way, they had encountered countless pirates: cunning ones, cruel ones, hypocritical ones. No matter what kind of skin those pirates wore, they all shared one trait: greed for wealth.
Yet what they sensed from Luffy was purity and simplicity. Put another way, calling him a little slow might have been more fitting.
After some consideration, Kuina ultimately did not attack that airheaded boy. Although every sign suggested that Luffy was no ordinary person, she simply regarded him as a lucky fellow who had happened to eat a Devil Fruit.
The New Marines disguised as a merchant ship were not headed in the same direction as Luffy's little boat. Although they had learned from Luffy that Colonel Morgan had been exposed and detained by the Marines themselves, Kuina still decided to personally head to Shells Town to verify the matter, just to be safe.
Before leaving, Kuina kindly asked whether Luffy and Koby needed help getting back to town. Even after being refused, she still left them some fresh water and supplies.
The journey from these waters to Shells Town was not short. Even a merchant ship like theirs, with its large sails and favorable winds, would probably need nearly a day and a half.
A small boat like Luffy and Koby's might not even reach the nearest island smoothly in two days.
Although Luffy and Koby had not yet shown any distress over their lack of supplies, warmhearted Kuina still offered them some assistance.
Once the supplies had been moved aboard, Luffy's impression of Kuina, Zoro, and the others changed completely. Because of