We never reveal our methods. She once opened her door to find it on her door step, with a little hobo stick to which was attached a letter claiming it had ridden the rail cars across the country.
I got it back contained in an official parcel from a local lawyer with a 'cease and desist" letter.
Before my father passed away he had a heat-sensitive mug that read either Seize the Day or Carpe Diem. My sister and I now exchange that mug as often as possible but always in devious ways. This has been going on for years.
At her last visit, I made her empty her suitcase when she arrived...