It has become part of everyday life in the capital to use your card or phone to tap in to travel on the transport network.
But ITV News has uncovered an operation that penalises people who do just that to travel to London Stansted Airport.
Despite having contactless payment systems activated on the gates of the Stansted Express, thousands who don't have a physical ticket are being given large fines of up to a hundred pounds.
The travel watchdog has questioned how Stansted can be the only airport in our region that doesn't allow ticketless travel.
Passengers who didn't spot warning signs before their trip have described it as a money-making scheme.