checked with a buddy that works at a new car dealership and he says it is a MUST to disconnect battery cables now a days and some makes and models both cables disconnect both cables and air bags. have you ever had air bags go off when car was sitting still, not running when the bags went off? not pretty
I have welded on hundreds of cars with air bags, never had one go off. Never had one go off in our shop, at all.
During my certification, I was told an air bag can theoretically go off, while carrying it across the shop, from static electricity. Never saw that happen either.
They also told us, that you couldn't switch a cars a/c system from R12, to R134, without flushing out ALL the oil. Because, the PAG oil was not compatible with any of the mineral oil from the R12. As cars got older, and people did not want to spend a lot of money on them, so shops started just swapping everything and not flushing it. And, everyone found out, it worked just fine.
If the dealership wants to require the techs to do something, it's their money, they have that right. Nothing wrong with an over abundance of caution. But, it's not always necessary.
No manufacturer recommends jacking up a car without putting on the emergency brake either. I guarantee you that dealership does not require their techs to do that.
