Police say the gang has worked Vancouver's airport and nearby hotels twice before and is expected to try again. Among their favourite targets are Asian travellers.

'Their assumption, which seems to be correct, is that many Asians carry large amounts of cash,' says Sergeant Willy Laurie, of the crime prevention unit of the Richmond Royal Canadian Mounted Police.

The thieves 'have all sorts of interesting ways' to separate passengers from their belongings, he says. They may spill ink or food over a victim and then fuss over the cleanup while a partner walks away with the goods. Or a beautiful woman may say something in a whisper to a man. When he leans closer to hear, she reacts angrily and storms off. While he's still wondering why, her accomplices have vanished with his luggage.

'They never work alone,' Sergeant Laurie says. 'When we do surveillance, they do counter-surveillance. If they sense our presence, they're gone.' They also study their victims. A couple might have six bags on a trolley while waiting in line for a boarding pass, but because the criminals have watched them taking care over a certain bag, they know which one to grab.

Sergeant Laurie estimates that 90 per cent of the thefts could have been avoided had the victims paid attention.

'I was trying to explain this to a TV news crew one day at the airport. So I said, 'Why don't I show you?' I walked right over to a couple, picked up their bags and walked away, with my uniform, the TV cameras and everything. Nobody says a thing if you just act like they're your own bags. You could fill a semi-trailer with stolen luggage in no time.' He advises travellers not to carry large amounts of cash, and 'if you're approached, be careful'.

'A lot of people get an ESP feeling when something might be wrong. Learn to believe it.'