There is no guarantee that the driver is oblivious to the conversation or unknowledgeable about the language spoken. Some taxi drivers may be used to collect specific individuals from the airport or hotel for the specific purpose of overhearing or recording a sensitive conversation. Many businesspeople carry sensitive documents and laptop computers with them when they travel. This can place their information in a vulnerable position. Documents can be photocopied or photographed when they are out of your possession.
Laptop computers can have their files copied.
Restaurants, hotels, foreign company offices, can all offer brief opportunities for documents or laptop computers to be compromised when left unattended. The easiest solution is simply not to carry valuable information with you when you travel. If you must carry sensitive information with you, try to keep it small, concealed and easily stored on your person. Key information can be kept on a diskette or reduced to cue-card sized documents and enlarged later. Luggage checked onto an airline is vulnerable to interception.