I did something worse once in HKG.

I was flying QF back to SYD and of course I used the Wing instead of the substandard QF lounge. However on my way to the QF gates (a fair walk from gate 2). I went to the RELAY shop to get some magazines and I accidnetally left a whole bag of duty free shoppign there.

I only realised I left something when I arrived in SYD and I thought it was on the QF flight, so I asked the baggage service desk to page the fligth dispathcer. But no bags there.

I emailed the MPO and within 2 hours they tracked down the bags and send it on the first flight back to SYD! I am so surprised they managed to do this.

Also did not cost me a cent and I picked up the bag at the airport in the evening.