Gatwick to Barcelona about 13 years ago. Me, the not-yet-ex, a toddler and a baby. When we arrived at security I was for some reason carrying the n-y-e's backpack. When we got to the aircraft door I realised that we'd left it at security. (Because I had checked that I had *my* stuff and the *kids'* stuff). I hurried back there to see it on the floor with the security bods. Pointed at it and asked to retrieve it. Security bod then picked it up and plonked it on a desk and slowly and carefully started unpacking it - small cuddly toy, packet of biscuits, "my first words" book, etc. I pointed out that it had already been through security and if I waited any longer I'd miss the flight. I was a bit frantic. "You're not helping yourself, sir" was the response. I asked that if I left without it would it go to lost property? "No guarantee" was the helpful answer. I gave up and hared back to the gate. (If you really want people to stop and stare at you, running full-pelt through an airport is as good a way as any).
A few days later a relative who lived not far away *was* able to retrieve it from lost property - so no loss in the end, apart from my respect for Gatwick security personnel.
(BTW - pprune's spell-check seems to be American? Prefers "realized" over "realised").