A house I bought years ago had a gnome in the front garden, which I 'inherited'. I came home from work one day to find he'd vanished, and a note demanded 500 red Smarties for his release. (Can you imagine how many packets you'd have to buy to get that many red ones?)
Needless to say, I didn't pay the ransom, and he reappeared months later, on the roof of my garden shed, wearing a stocking mask like a bank robber!
I think you're right about it being a common crime, Mary, though I hope gnomes don't come alive at midnight - Eek! that's the stuff of nightmares
