In the "real world" (or "bigger world"), businesses are always relying on third parties. Most commonly, retailers use a person's drivers license (issued by a third party, the state) to determine whether they will sell that person liquor, tobacco or admit the person to an R/X-rated movie. And these businesses continue to do so even though they are fully aware that there are people who make a living by producing fake drivers licenses. As of today, I'm not aware of anyone making a living by producing "fake" certificates.