To help the reader better understand the plot, and the setting of the poem in which it takes place.
In my opinion, there are two possible reasons.
First, the government probably does not think these guys are any kind of a threat to them. I mean, so what if there are some people out walking around when no one knows they're there? It's like the thing about the tree falling in the forest with no one around.
Explanation:
just write a nice perfect letter