Police raided an industrial building in Kwun Tong today and shut down a phone scam centre. They say the triads were running it.

Twenty people were arrested. Police link them to at least 16 scams, worth about HK$1.3 million between the victims.

Look at that for a second. Twenty staff, sixteen cases. That is an office with more people than clients. It even has a unit in an industrial building, which is where many of Hong Kong's small businesses live.

Here is what people forget. A scam centre is a workplace. Somebody finds the premises and somebody pays the rent. Somebody sits at a desk and makes the calls, all day, to people they have never met.

That is why the industrial building is such a good hiding place. Nobody looks twice at a unit in Kwun Tong with the door shut. Lorries, cardboard, people carrying boxes. A room full of people on phones fits right in.

It also means a gang like this has overheads. It is running a business, and a bad one, with the triads as management. The victims paid for the desks.

I will not guess how the calls worked. What matters is that the number on your phone can be a room in Kwun Tong. Twenty people in that room are now under arrest.

If a stranger rings and gets urgent about your money, hang up. Then call someone you trust.