WARNING. We made the mistake of accepting an unofficial "taxi" at Hong Kong airport.
At HK international airport a "gentleman" was asking if travellers needed a taxi. It turned out to be an "unoffical" mini van with no meter. We asked how much and were told $98 HK plus tolls.
We we arrived they want $980 plus $300 for tolls (they were $30 HK). The doors were locked so we could not get out until we paid. These guys are organised criminals. We found out that this was 10 times the real cost.
HK is well run and orderly in the main. Make sure you only use the official government registered taxis (red sedans).... We will report these criminals to the police but be very careful.