Let me say first that I am sorry to hear that your daughter had this experience. That being said...

I never would have purchased my son one of these, but his grandmother did when she was without a suit for him. I tend to use this suit every time we are at the lake now, just in case he happens to hit a drop off or go out a little too far. Often times I'm watching from the beach instead of in the lake, so the suit would buy me a bit of time and keep him afloat so that I knew exactly where he was. I can understand how this suit might make it difficult for a child to flip over if they happen to hit the water chest first. HOWEVER, I'm sure that most likely, the label does not in any way market this item as a life saving devise. Adult supervision is the only way to make sure children are safe around water. I kind of equate all of these floatation devices with baby walkers...many accidents may occur each year, but it's usually because an adult has a false sense of security when using them.