Pocketpickers' code 101: credit cards in the UK are sure bets. Forging a signature is a swizz.
When I discovered my wallet missing, I had a flashback to a coffee shop in Piccadilly and the few seconds I'd left my jacket and the zipped-up wallet unguarded.
But that wasn't how the theft happened.
When my wife, Mary, phoned the bank to stop transactions on our credit cards, she was asked about several purchases that had just shown up - gear worth several thousand dollars, some of it bought from a Piccadilly shop, some ordered online, and another transaction at Vauxhall Bright Station - NZ$192 loaded into an Oyster card, for use on London's trains and buses.
I'd recharged my Oyster card at an automatic booth in Vauxhall Bridge underground, using my credit card, which I put back in my wallet and zipped in my jacket pocket.
Train stations are notorious for pickpockets and bag-snatchers - professionals noting everything about the way you stand and move and certainly noting if you've put a wallet in an external pocket. The stations are crowded at rush hour. You pile on to the crowded tube. It's a noisy crush. You rub shoulders. Like me, you may emerge, blinking in the light of day unaware your jacket has been relieved of a wallet.
The bank staff were sympathetic and assured us we'd have new cards within a few days, the pick-up point being a Paris hotel. So our trip wasn't ruined by some low-life latter-day Artful Dodger.
Around London, the word is that pickpockets are more active than ever. Londoners blame the European Union and open borders for increased crime.
Note, too, that banks and shops are slack about making PINs mandatory. Anyone can present a credit card and forge a signature. Our bank said we would not have to pay for the fraudulent use of our credit card.
Watch your wallet. Keep it hidden under clothing or secure it in a zipped bag around your waist facing forward.
At Paris' Notre Dame Cathedral an entry sight warned visitors to refrain from smoking, to maintain silence - and, yes, watch for pickpockets. Thieves operate even in the most sacred places.
Pickpockets or bag-snatchers strike anywhere. That's a given. A decent cup of coffee is not.