What is the significance of the “man with the megaphone”? What do this and other details tell you about the setting of the novel?

The man with the megaphone would have been the adult in charge of the boys. The fact that he's gone tells us the boys are stranded on an island without adult protection or supervision.

The man with the megaphone would have been the adult in charge of the boys. The fact that he's gone tells us the boys are stranded on an island without adult protection or supervision.