Forgot the noise cancelling headset to the fitness room at Four Seasons Lanai and they disappeared. My fault, no idea if it was the staff or guest who thought they were keepers.
I left the Verizon MiFi thing on the dashboard in the car and while it was valet parked here at Grand Hyatt SF overnight, it was gone. That's pretty stupid thing to steal, it had a prepaid account with just ~2 weeks of capped data left and I would assume I can report the IMEI code to Verizon so that it will stop working for good, like one does elsewhere if a phone is stolen.
From this perspective it's more fun to travel in less developed countries. They care about their precious jobs so much that they won't even consider stealing, their job is their lottery win. In North Korea even the lighter I intentionally left behind was still on the same desk when I returned to the same hotel and room a few days later. And if something gets stolen, it's a piece of clothes or something that someone really needs (we've never had anything else stolen on our travels).