Thats not quite 100% failsafe. MB had a bunch of car seats (one design of the baby rock-a-top) which they recalled and re-designed the sensor layout - what was hapenning was the seat was moving slightly and sensor going out of range.
I suspect that the issue that then gave was if car was stalled or off/on like at a petrol station, it is unlikely the lamp would have been checked.
I love the auto-sensor thing. We also have a BMW and that has a keyswitch, we're very good at making sure airbag is off if child seat in front (all 7 seats needed for school run), but not so good at turning the airbag back on again
Almost all UK spec mercs (since the mechanism was available) have had the sensors in the car seat. Apart from the 07 ML (and probably some other 07 cars) where they dropped it from the standard build and UK didn't put it back on as standard on UK cars for 6 months. To add confusion the cars still had the airbag off light, which still lit up briefly as you started etc. You only knew by looing at the sticker on the end of the dash, or the datacard.
My 07 ML came without it, and to add it in theory you need a new airbag control module as once coded it is locked. I added it but used factory mode Star Diagnosis to change the setting to match another car which did the job (and then added it to the datacard so that any future owner wouldnt get a wrongly coded airbag module if it was ever replaced - although of course it was flagging up that the sensor was the wrong type until coded correctly for the sensor). Adding it meant replacing the occupancy sensor mat in the seat for one with occupancy setting and AKSE
Richard
