Side/window Air Bag problems of the 2003 Mercedes Benz 230

I have a 2003 mercedes c230 with 80k miles, the car would stop running either while idol or driving down the road. Took it to the dealer, replaced O2 sensor, next week same problem, replaced 02 sensor again, it died again while at the dealer, dealer then explained the oil harness leaked into the 02 sensor and knocked out the cam sensors and crank sensor as well, so they replaced those parts plu the harness and subharness. I understand from 2007-2008 mercedes service blogs that "seems to happening on the m271 motor's (2003-2005 c230); the cam sensors leak oil were the wire goes into the sensor, then the oil travels down to the O2 sensor and kills it; if oil gets in the harness and damages the O2 sensors, not only do you have to replace the O2 sensor but that entire section of wiring harness; prevention is the key. . . Also, mb has a harness that is supposed to prevent the oil from getting in the rest of the harness. . . " so my question is why hasn't mercedes (mb) been required to recall this part before it causes more serious problems, such as an accident from stalling or an auto fire?.