... and it could be argued that people who are, ahem, slightly less advanced/sophisticated than others in the game have their input at this stage, too.
The 'expert' would never do [this or that] because it would be a silly thing to do, even with a fully developed OS; the more naïve, otoh, might not know not to do it. And the problem would not be disclosed until the so-called fully-tested product was out in the wide world. Mega thread-drift coming up...
back in the 60s, Vauxhall produced a family saloon called a Cresta. Not long after its release, someone came back to the dealer with the front screen across the back seat.
Shock horror: "What HAVE you done?" "Nothing much, I just jacked it up in the drive and the windscreen popped out. What do you mean, it can't do that. It did. Er, possibly I shouldn't have had the front door open at the time."
The salesman insisted that it still couldn't happened that way, until the punter insisted in his turn that they try it on a car in the showroom, so they opened the front door, jacked the car up, and guess what? The windscreen popped out.
Us idiots can be useful at times.