The problem in using your example is this: in the scenario described, the slower scouts were at least attempting to complete the hike. The slowest person in a poly tangle is not always attempting to complete the hike--sometimes they're simply engaging in a bit of denial and hoping the whole thing will go away.
The trick lies in figuring out if they're attempting to work through the process or simply dragging ass while hoping it all goes away.
When speaking of various forms of non-monogamy...it ain't poly if you're just fucking around.
While polyamory, open relationships, and swinging are all distinctly different approaches to non-monogamy, they are not mutually exlusive. Folks can, and some do, engage in more than one of them at a time--and it's all good.