I'm not 100% sure if this could be called foreshadowing. But you guys remember the conversation between Gon and Chrollo? Gon said "How can you kill those who have nothing to do with you?" I can't remember what Chrollo response was, but Gon here was quick to tell someone off for getting innocent people involved in their affairs. But then we get to the Chimera ant arc, and what does Gon do? Threatren to kill an innocent girl (Komugi) if he doesn't get what he wants. He even goes far as to take her hostage, and judging by Gons expression in that scene, it looked like Gon was serious about killing Komugi. So Gon tells someone off for involving innocent people in their affairs... But does the same thing himself. It shows how we are quick to judge someone for doing something we don't agree with, but at the end of day we can't really judge those people because there is no garuntee we won't do the same thing or something similar.