Dozens of ticket touts – or ‘yellow cattle’ as they are known in China – are targeting unsuspecting tourists, just yards from the Olympic area in Beijing.
They have made near-perfect copies of tickets and are charging up to £120 each for the best athletics and football seats in the Bird’s Nest stadium.
But when the fans pass through the stringent security checks, they are turned away and told the ticket is fake.
Police say they have stepped up patrols around the Olympic venues following complaints from the public and have arrested 221 touts – 31 of them tourists.
But when a Sky News team visited the area, there were still dozens of touts openly selling tickets in the street.
Olympic volunteers, in the distinctive blue and white uniform, have been sent into the crowds to warn tourists about fake tickets.
Our undercover team was offered two wrestling tickets for 400 yuan each – about £32 – four times their face value.
Two Olympic volunteers then stepped in and warned us the man was ‘yellow cattle’ – and the tickets were likely to be fake.
“You should make sure it’s true or false,” one said. “If you buy, you will try to go in and be very angry.”
Other touts are selling genuine tickets, but for hugely inflated sums.
We found one Chinese man selling tickets for Monday’s US v Japan women’s football semi-final for 50 times their face value.
He had bought the heavily-subsidised tickets through a Chinese educational scheme for just 10 yuan each – and wanted 500 each for them , or about £41.
He said: “I have to work, I have no time to watch the game. I am too busy.”
But it did not stop him standing for hours outside the security entrance to the Water Cube building, trying to get the best price for his tickets.
Another man tried to sell us tickets to the same game – they had a face value of 300 yuan, and he wanted 1,500 (£123) each for them.
When we questioned the price, he became aggressive and followed our team for 20 minutes shouting: “You want ticket? You want ticket? If you buy, I’ll give you good price.”
In the end, he offered them to us for 1,000 yuan each.
We also found a man from Hungary selling tickets for athletics events in the Bird’s Nest stadium for 1,400 yuan – nearly four times the face value.
When we questioned him about their authenticity, he replied: “Of course… they’re not fakes. They’re real.”
He then pulled out some used ticket stubs from his pocket, supposedly as way of proof.
Because of the number of foreigners involved in the scams police have set up signs in English warning that ‘scalping’ – as it also known – is illegal.
Police said a tourist was detained for selling 24 tickets near the Water Cube at 10 times face value – but refused to give further details.
Another man, whose nationality and name was not disclosed, was in custody for allegedly selling two 300 yuan tickets for 1,000 each.
Police said he had bought 130 tickets in Italy and sold more than 60 at different prices since arriving in Beijing.
Shi Weiping, an official with the Municipal Public Security Bureau said, of the 221 people arrested, 71 were in custody, including three foreigners. The rest were released after being given warnings.
Olympic bosses said they had repeatedly warned that “resale of Olympic tickets for profit is illegal” and vowed to “support the authorities to crack down on suspected illegal transactions”.