Last night at work, I dealt with a party of two, who had connected from an international flight at SFO, and then arrived at my airport. Their bags were not here so I did a search and saw they’d failed to p/u bags at SFO, clear customs and drop off at the reflight belt. So, they were still sitting at SFO. I explained why the bags were still there and that at their first point of entry to the US (unless traveling from an airport that had US preclearance) they ALWAYS had to retrieve their bag and recheck.
While I filled out a delayed baggage claim, they stood there for a good 10 minutes telling me they were frequent fliers, I was wrong, and this was not how it worked; there was never any need to clear customs and recheck bags, it was automatically done for them.
I hear stuff like this every day. Enough said.