The PADI OW class video has a whole section on inspecting your BC and other equipment for possible problems, before you even assemble your gear. For a long time, I thought it was overkill, but over time, almost anything that CAN wear, break, come apart, tear, untie itself, or otherwise malfunction, has. I tell myself over and over again that I just need to LOOK at all of my gear as I set it up, rather than throw it together. Cave line working on untying itself, and mouthpiece flanges almost chewed through, would be found by doing that. I think that's the biggest lesson from this story. Gear ain't right unless you KNOW it's right. In the wrong situation, this malfunction could have been a very bad one.