I understand you're not aware of a large number of SERPA-related suits. My point was, were you aware of the large number of suits related to Glock's takedown procedure? Lots of things like that happen in the industry without becoming widespread broadcasts. In most cases, settlement stipulates no public comment or disclosure by the injured party.
Regarding the issue of design flaw, perhaps we're just using words differently.
If an auto manufacturer created a system that used a single pedal for both gas and brake, pushing it slightly more right for gas and slightly more left for braking, you could certainly argue that someone adequately trained who does it the right way would never have a problem. But nonetheless, I'd bet big money that you'd see a lot more accidents with the one-pedal car when drivers made the car stop or go when they wanted it to do the opposite. Just because it's user error doesn't absolve the equipment.
The world is full of consumer products that have systems designed with human factors in mind to prevent accidents or injuries. The grate over your desk fan's blades isn't there because the manufacturer thinks you'll purposely shove your hand into the whirling maelstrom; it's because they understand that humans are capable of making mistakes. They design their product with that in mind and try to minimize the chance for a mistake.
We have some pilots on the forum. I bet they could tick off a long list of anti-pilot-error features on modern aircraft. As I said earlier in the thread, airline pilots get more hours of training, more scientifically tested and proven training, and more realistic training than probably 99% of the gun owners on the planet. Yet every year, a few of them frak up and kill a bunch of passengers along with themselves. If a seasoned professional pilot can have a brain fade and forget to put his landing gear down during a routine approach, it doesn't take much humility to admit I might make a mistake when confronted with sudden unexpected life-threatening harm.
It's not a black and white, either/or kind of problem. Yes, there needs to be operator error for an accident to occur with the SERPA. Guns don't spontaneously discharge in the holster without contact by a human being. But at the same time, there is plenty of evidence to show that the design is fundamentally more prone to those kinds of accidents. Many of us were able to predict that when we saw the prototypes however many years ago.