This is my 5th BMWs and BWM do break down.
I had a E46, the fan belt broken while i was driving on a highway, engine immediately loss cooling (water pump was driven by the same fan belt), i kept driving for about 1km and eventually had to stop as the engine temperature reached to 150C and warning light was on. The warning triangle helped to warn other drivers on the highway while my car was stationary.
Later i found that the fan belt failure was due to a tensioner bearing failure, mileage was ~ 50,000km at that time.
I also keep a small fire extinguisher in my other BMW car(///M), as a prevention for myself and others unlucky diver.
Photo taken yesterday on the same highway that my E46 broke down.