I think one of the biggest things we assume is that when someone tells us something we just take their word for it. If she bought this at a craft show then there really is no way of knowing what was actually used and of course the seller would say she has no idea why that happened. Not saying there was any ill intent, simply saying some people don’t put a lot of effort into things they make and may assume a fabric that looks like cotton, so it must be cotton, all thread must be cotton or did not know there was a difference, the same applies to batting. I think this is one item that should be made by the person using it just to be safe. Trust, but verify…..