Here's a pull quote from a UAC blog post by Bruce Tremper, found here:
https://utahavalanchecenter.org/blog/15943
My pet peeve with this issue is that people who argue about the numbers often leave the most important part out of the discussion--terrain. If you get caught in un-survivable terrain then, guess what, you won’t survive no matter what kind of rescue gear you use. There have been a number of prominent accidents in which the victim with a deployed airbag died because he was either strained through thick trees and rocks, deposited in a terrain trap, buried deeply or went over a cliff. In zero-tolerance-for-error terrain, airbags don’t work, beacons don’t work, Avalungs don’t work. Nothing works. Save your money, buy a life insurance policy and a beacon or RECCO so rescuers don’t have to spend all night probing.