Yeah, people don't understand how dangerous motorcycles are. The fatality rate for motorcycles in the US is 23 per 100 million miles traveled. For cars that number is 0.7. Assuming you ride 4,000 miles per year for 40 years, that gives you a 4% chance of death. The chance of being crippled or receiving a brain injury is probably higher than that.
That feels like a very different scenario. A successful test would still leave me winded and bruised. The odds of failure are much higher than 1 in 100,000 per year. I also have no need for a bullet proof vest so why would I be interested in testing it - what's the benefit to me?
Virtually everyone will opt out of the test, because the choice is not, "I'm going to shoot a gun at you as a test. Do you want the experimental bullet proof vest or no bullet proof vest?"
Not if the vest suddenly decides to malfunction and explode or otherwise do something that kills you. Good lord there is some poor logic happening in this thread.