Lurking in the arrival hall, they seek out foreign visitors who look disoriented and ask: "Taxi?" The unsuspecting tourists are then ushered past the Warsaw airport's official taxi stand and into the unlicensed and meter-less cab.
An expensive surprise will likely await the passengers at the end of their ride. While the fare for a lift into the capital's city centre costs on average 40 zloty (about 10 euros) with a licensed operator, the same journey with a black-market driver could cost the riders up to 140 zloty.
The Warsaw taxi mafia has struck again.
Drivers who operate without licences are looking to make a big profit during Euro 2012, which will be co-hosted by Poland and Ukraine from June 8 - July 1, and is expected to attract thousands of fans.
For years the Warsaw city council has been waging a battle - largely unsuccessfully - against taxi scammers. And although the city has cracked down on the illegal activity ahead of the championship, the drivers are more present than ever in the airport arrival's hall.
"We may have to eventually prohibit anyone from standing here," said airport spokesman Przemyslaw Przybylski.
One small success is the new official taxi stand that is run by the airport authority. Prior to its existence it was not uncommon for members of the taxi mafia to have to be ousted from the area with baseball bats and brass knuckles.
Experienced travellers arriving at the airport often go to the departure level to intercept a licensed taxi that has just dropped off passengers.
Yet even outside the airport the taxi mafia can be hard to avoid.
They often wait in front of train stations and hotels for unsuspecting victims.
But illegal taxis are actually easy to spot. All drivers who work for an official taxi company have to display their licence. There should also be a logo and telephone number of the company clearly visible on the side of the vehicle. A list of fares, with higher evenings and weekend rates, should be available.
Meanwhile, local newspapers report scams that also trick passengers on the fare listings.
The city government can do nothing in such cases: "The tariff is a matter for individual companies," said Joanna Tyminska of Warsaw's regulatory authority.
The situation is somewhat different in Ukraine. Most taxis do not have meters and most drivers work illegally. The price is normally negotiated before the ride - something unfamiliar to most Western European travellers who may suspect a scam, however drivers usually keep to the agreed upon fare.
Only the official airport taxis in Ukraine are equipped with meters and therefore more expensive.
Making a taxi reservation by phone has become standard in Ukraine.
The call centre will agree to a price before it sends out a free vehicle. It should not cost more than 12 euros to travel across the capital, Kiev.
There are 20,000 to 30,000 independent taxi drivers in the city.
According to media reports, they will face greater police scrutiny during the games and are thus likely to "disappear" during the tournament.