Not kids, but my mother?!
I needed to travel away urgently at short notice on business but I was expecting an important delivery that I needed to take with me. I got notification that it was delayed and wouldn't arrive until after I'd left. I diverted the delivery to a post office collection point so that my mum could collect it on my behalf. They needed something like a driving licence or passport for ID so I left my driving licence with her.
She collected the item and then forwarded it on to me by post. I opened the box, took out the item, threw away the packaging in a huge recycling bin at the commercial premises where I was working.
She texted me about three days later to check it had arrived safely. I said yes it had, and she said 'And did you find your driving licence?'
'What?! No! Where was it?'
'I hid it between the folds of packaging that were protecting the [item] in the box.'
'What? Why the hell would hide it, without telling me first?!!'
Well I was worried someone might nick the parcel and open it so I didn't want them to take your driving licence too. I figured they probably wouldn't have found it hidden in the wrapping.'
'Yes but mum, I didn't find it either! Aaaargh!!!'
I rummaged in the enormous commercial recycling bin, took out all the cardboard, but no luck.