I recently saw a video of someone at a match who's detent came loose and got stuck in the trigger group, disabling the gun. The video was posted as an example of why the buffer detent is a bad idea. I'm wondering what the P-F consensus is. I've never seen one fail myself and it seems like it shouldn't but at the same time it doesn't seem neccisary and is a potential failure point.
Original video. It looks like the detent is in one piece so the first thing that comes to mind is that the buffer tube wasn't screwed in all the way. But I don't really know how it happened.
Another talking about why they're not neccisary.