Patience with me says the man who thinks statistics have no scientific use and you can't prove whether an airbag would make an object rise to the top of a pyro-plastic flow (thanks Ghost)?
How do you test car safety? You put crash test dummies in cars and crash them. How do you test avalanche airbag prototypes? You strap them on crash test dummies, start an avalanche, and see if they get buried or float. I mean, you could scour the local colleges for desparate students looking to make some cash, but you might get in trouble with the authorities for testing on humans. If the crash test dummy is such a bad tool for safety testing, then someone might want to notify the auto industry. Personally, I'd take crash test results and statistics showing higher survival rates for airbag users over a few individual accounts, but that's just me.
And you're right, I've never been in an avalanche. But, the off-piste instructors and guides I've skied with from the Arlberg Ski School, as well as the ski patrollers in Val d'Isere, all wear airbags, and I'm guessing they probably know a thing or two about the dangers of avalanches given the amount of debris I see in those resorts every time I go there.