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Hahaha. No comment. :)

(we took it to the parking lot / visitor centre hoping someone just forgot it there)

Good call. Like you said, it could've been reused.

I've got loads of stuff that people left behind - usually at festival - like foldable picnic blankets, handy heavy-item wheeler, a pristine backpack.
Once, I found a MASSIVE bag of weed hidden in a sun glasses case. Although, I don't think that was left intentionally.

hahahah! epic resell value. :)