Happily, I can report the BAA's information staff are trained in body language.
A Sardinian woman asks if it is easy to find a taxi at Heathrow. The answer she gets is a cheery British thumbs up. (Very likely from one of the 900 cabbies who serve the airport on an average day.) Immediately, she clonks the unfortunate man whit her handbag for making such a devastatingly insulting suggestion. This is why, incidentally, is's not a very good idea to thumb a lift in Sardinia.
Isn't there at least one truly international gesture? Don't bet on it.
A Japanese asks an American passenger whether Heathrow has a luggage trolley service. It has. And as it happens, this service is not only first class, but FREE! So the Yannk replies with the famous 'A-OK' ring gesture. But to the Japanese this signifies 'money' and he concludes there is a large charge for the service.
Meanwhile, a Tunisian on-looker thinks the American is telling the Japanese that he is a worthless rogue and he is going to kill him.