People on a nature walk with nets and backpacks with trees to the left of them.
People on a nature walk with nets and backpacks with trees to the left of them hope to return to camp before sundown.
Not all people on a nature walk have a camp to return to; even if they do, they don't necessarily hope to return to it at any particular time, let alone before sundown.
Just because people are on a nature walk it does not mean they hope to return to camp before sundown.
Only becuase people on a nature walk doesn't necessarily imply they hope to return camp before sundown.