This is how we learn. This guy stood up, owned his issues, and explained the situation so that others could profit from his mistakes. This particular issue, having ANYTHING inside the trigger guard until you are ready to fire, applies to pistols as well as rifles. I'm training my young shooters to keep their trigger finger in one specific spot, well away from the trigger, when drawing and to only move their trigger finger to the trigger when the pistol is pointed at the target and they have decided to shoot.
I will have to admit that I had never heard of such a bolt release device as this. When he demonstrated the process, I felt a visceral reaction. It was scary. I have only recently entered competition, having completed three matches. Muzzle direction is tightly monitored during a match, but that did not prevent this ND.