I used to enter a lot of competitions, and won quite often. I once had a vacuum cleaner delivered, with no information about where it had come from. I presume that it was a prize, and just hoped that it wasn't a wrong delivery.
My daughter in Australia once asked me to buy a £100 gift voucher for her friend, who was getting married, and deliver it to her. I duly did so, posting it through, as there was no-one home.
A few days later, chatting to DD, I found out that her friend no longer lived at the house I had delivered the voucher to. I dashed back, and the bemused lady, who had been puzzling over the mystery gift, returned it to me. Thank heavens she was honest!