Btw, in both instances, the steering wheel was inverted at the time the unit separated from the wheel. The photo shows it with the wheel returned to center, but that's not when it came off either time. I was definitely uphill in the second instance.
I looked into airbag design a little bit, it appears there's usually chain of events that leads to the deployment (ie. concurrence from multiple sensors, not all of which are in the bag itself, if any at all, in fact). I realize the gut reaction is absolutely alarming, but putting that aside, through what mechanism would the airbag deploy if the housing unit detached from the wheel? This is an academic discussion, of course, the car is being flat-bedded, period, however, I'm just trying to ascertain the actual practical risk beyond the sharp inhalation that results from the use of the words "the airbag fell off."