I saw my bag being offloaded from an Aer Lingus (BAe 146) flight to DUB from LCY. The aircraft was overweight - they offloaded some volunteer pax too, though they never mentioned the bags. I wasn't too worried about it at the time because I felt sure it would get put on the next flight from LCY or perhaps even one from LHR - so there were plenty of options that day.

My bag was visually unique - it had my company name emblazoned on it.
It had a metal bag tag, with the same company name on it, also containing my contact details complete with a hand-written message requesting that the finder contact me to return the bag (for a reward).
As a backup measure, I placed my business card with the same hand-written message inside the bag itself.

I never saw that bag again.

There wasn't anything exceptionally valuable in the bag, but it was a colossal inconvenience having to replace all my clothes - I hadn't built "shopping time" into my agenda.

I imagine that the bag eventually ended up in one of those auctions. I am a little disappointed that the eventual finder never bothered to contact me. I would happily have paid for the return of my clothes.