Not dumpster diving, but I once spotted two near-perfect bag chairs folded up & stuffed under a scrub pine at the rear of a downhill empty site. First week the OBX NPS CG at Frisco was open, so they'd probably there all winter.
I waited several days, but the site stayed empty & no one came to get them. Nice chairs; high backs, arms, drink holders. Scrubbed a little pine sap off of them, and they lasted me 10 years ;). Just replaced them this past spring.
Jim, "I'm right 97 percent of the time. Who cares about the other 4 percent?"