Twice. One was real. A frame got stolen from my back garden and then I saw it a week later in a second hand shop built into a bike. I’d not recorded the frame number so it was pointless pursuing it. I told the shop but they didn’t care. Quite obviously my frame though, rare and with all the same scratches and dings.
The better one was when someone broke into our flat in Manchester and stole my wife’s bike. One the way back from the police station I saw it chained up to a park bench. Incensed I returned to the flat, told the wife I was going to sort out the thieves, tooled up and marched back to the shopping centre. 4 hours I sat there. Waiting….
Eventually my wife came to find me, took one look at the bike and said it wasn’t hers. Hers had a big scratch on the top tube. Oops. 😉