I'm a relative newcomer to pistol shooting.
I wanted to get into IPSC last year so I took the 2 day black badge course which is mandatory in Canada to be allowed to draw from a holster at the range.
At the time I only had a 1911 so I purchased a CR Speed race holster which only covers the trigger and has no retention device of any kind.
The holster is made to play games where speed is of the essence.
I then bought an HK P30-L to compete in production division and I bought a Serpa level II for it. In the 6 months I've had this holster practicing for IPSC I've never stuck my finger inside the trigger guard.
Where I do run into problems is when I switch from the 1911 to the HK or vice versa is that I keep messing up my mag releases since the HK uses the trigger finger to release the mag.
Using multiple guns with different controls is azure way to mess up when speed is of the essence.
Tex did the same thing in that video.
He went from using the 511 thumb drive holster with a Glock to using the Serpa with a 1911.
The 1911 has the safety where the 511 thumb drive holster has the retention release mechanism. That combined with a hasty draw from the Serpa caused the ND.
One good way for shooters to increase their proficiency is to try competing in the shooting sports such as IDPA or IPSC where you are under constant scrutiny for such things as having a finger inside the trigger guard before your sights are on the target.
Let's remember blaming a holster for an ND is the same as blaming a gun for killing someone.