My 1991 300SEL shows an airbag replacement date of Sep 2000 on one of the plaques on the driver's door jamb. To my knowledge, the airbag has never been deployed (I bought the car in 1998, so I can't be positive, but the car shows no signs of ever having been in an accident). Is the airbag-replacement date a government-mandated "suggestion?" Anyone know if indeed an airbag loses effectiveness if not deployed in almost ten years?