This was given to me by a friend today, who had visited a recent Mardi Gras parade. His girlfriend found it while randomly scavenging around.
It originally had a red rubber band on it, but that ended up cut and lost, hence the regular rubber band to keep it closed. Thankfully it was never used though.
Why would it rust?
These things are used in forests where it rains, and when used they end up in the wet insides of a deer or in the damp wet ground in the forest. They are made from stainless steel, so they arent single-use, and doesn't rust up and get dull before being used.
The amazon link, someone else found above, also explicitly say it's stainless in the title.