I've watched this video 3 or 4 times since it originally came out several months ago. An interesting point of this video is that the video producer won't send his P320 in to get the upgrade - despite mentioning multiple times his concern over whether the pistol is safe or not. Sig Sauer has been turning round most of the upgrades within two weeks, which is probably the time it took to make this video. To me this speaks to the credibility of the piece - which despite its length is akin to tabloid journalism.
From what I understand, the "new" discharges are with upgraded P320s and not new 320s manufactured after Sig started the "voluntary upgrade" program and changed the sear, among other bits. Don't get me wrong, I'm not downplaying the severity of the issue, but when you consider the millions of P320s that have been sold and the extremely small number (by comparison) of accidental and negligent discharges I can't help but wonder if this a case being driven by lawyers. As for why Sig didn't just recall the pistols rather than institute a voluntary upgrade, IMO this was down to the bean counters - who were probably right. How else do you explain everyone not taking part in the upgrade program when all they had to do was call Sig to start the completely free upgrade process? Are the gun owners not concerned for their own safety? Clearly not. So this has been a win/win for Sig, because it has barely made a dent in the enthusiasm of the Sig buying market, they have the huge PR win with the military contract, and they didn't have to pay to fix every single P320. It doesn't make sense to me either, but not much in the world does right now.
By the way, I don't just talk the talk, I walk the walk. I have a P365 SAS, 226 Legion and a P320 X5 Legion, the latter of which I use for home defense and have put thousands of rounds through - not one of which has gone off without me pulling the trigger.