[PartialSchism]

I would laugh at anyone wearing plastic bottle flip-flops, simply because, they have plastic bottles, on their feet.

EDIT:
Also, Who's to say he's too poor to buy shoes? Because I'm sure there is a Wal-Mart within walking distance of everyone....
He/She could be the richest man/woman in the tribe or community.
Those could be a sign of power for all we know, while everyone else that person knows walks around barefoot, he's godly enough to walk around on plastic all day.