'JT' airbags are fitted to the sides of a lot of cars these days also. In the accident sequence described by the poster here there may have been a sudden reduction in fwd speed also hence the front airbags deployed.
I saw a wrecked Ford car at a wrecking yard once where I was after some spare parts & asked the yard guy about the Ford with the airbags just hanging there looking limp & he said that the driver had a massive heart attack brought on by the deployment of the airbags during that accident, sheez I thought it must be a hell of a shock when they go off!
Wmk2