http://pistol-training.com/archives/4926
That looks like it hurt! So, an Negligent Discharge that caused a self inflicted wound. What cardinal rule of gun safety did this very well spoken gentleman commit? Keep Your Booger Hook Off the Bang Switch Until the Sights are on the Target!
I've heard people complain about Serpa holsters in the past. I've owned them for two different guns. I've never used one for concealed carry because they are just to bulky to hide well. I use them on the range. I've never accidentally ended up with my finger on the trigger. Nor have I accidentally lit off a round. That doesn't mean it'll never happen.
I work diligently to prevent it, even going to so far as to avoid 1911s. Not because I don't like them or think they are unsafe, but because I don't want to complicate my manual of arms. Incidentally, Sig slide releases are in the same place as 1911 safeties. I've specifically trained myself not to ride that lever. Completely at odds with the 1911 manual of arms. That training habit would be just as dangerous to me as this man's was to him.
None of my carry guns have any form of manual safety. Under stress I don't want to think about which gun I'm carrying, I just want to know that when I pull that trigger, it's going to go off. Training back to back with two different holsters and two different guns is going to mess up your reactions and motions. That, IMO, is what really caused this accident, not a particular brand of holster.