I prefer never to claim absolute certainty of anything that I haven't known from conception to end. too many variables in life.
99.9 percent sure is pretty absolute to my way of thinking, but you never know, maybe one of the workers got really drunk and tried to make something and this is the inferior result. but the odds of that are amazingly low.
there might be flying pigs too. I am 99.9 percent sure that there aren't pigs with wings that are capable of flight. but there might be some mad man with a laboratory in the hills somewhere who has succeeded in some vile experiments..