Flying and cushions?

It's common to explain something to someone and then have them ask several questions that were covered in your initial explanation. This is because they were not paying attention. I was thinking about this when watching a stewardess explain the emergency exit protocol for my flight, and I realized that if there ever was an emergency, I was going to have a lot of questions. So, I paid attention. What I found was troubling. On my flight we were going over water, and I learned that, "Most seat cushions can be used as a floatation device in the event of a water landing." What's with this loose "most" talk? I'd like to know if my seat's going to float before I'm bobbing in 4-foot waves next to a flaming airplane. If there's ever an emergency and I ask, "Will my seat cushion float?" they'd better have an answer.  Just sayin.