If you keep pressing into your draw, WITH YOUR FINGERTIP. That's not how the release button is intended to be used. When someone NDs with a non-Serpa nobody blames the holster -- they blame the idiot user for doing it wrong.
The Serpa has a secondary retention feature -- the button is blocked when there's upward pressure on the gun. It is not easy to snatch a gun out of a Serpa.
But "Avoid jamming your finger in the trigger area" is very solid advice for guns. That has got to be the leading cause of NDs while drawing a firearm but someone does it with a Serpa and everyone is blaming the holster. Had my Serpa for years and it never even occurred to me to jab my fingertip at the button until Grebner's video.
IDPA never banned the Serpa. Some ranges / organizers have.
The problem isn't the advice, it is the reliance on the advice being followed without fail for a product that leaves very little safety margin in normal operation. It is like putting a factory reset button right next to the power button and expecting that the instruction to never accidentally press the reset button provides sufficient safety. Do you make the same allowance for guns that discharge when dropped? Surely the users know to not drop their guns, and yet recalls still happen. Foolproofing can look really silly when everybody is well rested and calm, but you might be grateful for the raised "Front Toward Enemy" when things get hairy.
You are correct about the IDPA ban, my mistake. It makes me wonder though, I can't think of a similar case of a safety rule being so charged. Green tip 5.56 is the closest thing that comes to mind, but that is more to do with property damage than safety.
The Serpa has a secondary retention feature -- the button is blocked when there's upward pressure on the gun. It is not easy to snatch a gun out of a Serpa.