I lived near UC Berkeley for many years and I would often take a random afternoon to drive around the student neighborhoods near the end of the term to snag a couple free things like air fryers, microwaves, or TVs for free. People would reliably leave them out on the curb for the taking as they packed up to head back home, since they weren't practical to take on a flight or long journey. I'm sure some people tried listing them on craigslist for a couple days when they started packing and then abandoned them instead when nobody bit, and some people probably didn't even care to go through that motion or waited too long to pack and realize they couldn't bring it.

Never went through the dumpster or got any "luxury" goods (probably wouldn't even recognize them if I saw them), but my wife did randomly bring home a pair of nice looking speakers that ended up being around $700 if bought new. I'm sure some wealthy international students do throw away some expensive stuff and not think twice about it. I actually did the opposite and tossed some of my own bulk items in a student dumpster once which was probably a violation of some kind although I didn't see any signs to say otherwise.

I saw some decently nice tvs or other things that could have potentially been resold by someone looking to do that, but I was only interested in taking something I would personally use.