I understand from a manufacturer pov, the design life of a vehicle is commonly ten years. Yeah, I know, there are vehicles running around out there from when the car was first manufactured (actually, there is a guy with a Model T at the end of my street - don't know its age). But the design principle still stands.
When airbags first came out as a mass provided item, there was a concern that the bag would not deploy properly after sitting dormant for 10 years or more, as the components may have deteriorated (bag, trigger device etc). LR is being conservative and ensuring that it is replaced due to age.
Experience in the USA, which was the first country to have a lot of cars with airbags (yes, Germany invented it - BOSCH (?), but the yanks are the ones who made it cheap by using pyros (ie the same mechanism as hand grenades, land mines etc), have had airbags successfully deploy after 15 to 20 years.
BTW, the explosive force in an airbag is about the same as a claymore land mine, so anyone with their feet on the dash (passenger side) or legs on the seat / folded in front of them will die a very painful death from internal injuries (legs into the chest and abdomen etc) if it deploys with them in this position.
Be careful around them and treat any maintenance around them with lots of respect, as they will take your head off (figuratively or in reality) if they go off with you too close to them and you are not in a normal sitting / steering position.
