What are the odds of that?
Yes, I know, insufficient data. But this story reminds me of the stories of people driving off a cliff, not being able to exit the car due to a stuck seatbelt buckle. Although it can happen, the odds are so low that that's no reason for not wearing a seatbelt. Similarly, I'd be very wary of not wearing an immediately functioning flotation device in case I got trapped inside a sinking boat. Methinks the odds of hitting my head and falling unconscious into the water, unable to operate a snorkel vest, would be noticeably higher than the odds of being trapped, unable to swim downward to get out of an overturned boat.