If it were a "hoax," it would be a pointless one -- yes, it would be stupid--- since the image is hardly discernible by the naked eye. You couldn't even see it, let alone make it. As pictorial propaganda it would be a "fail."
It's only very recent imaging technologies that have disclosed the surprising characteristics of this image, which were not even guessed 100 years ago.
Well, none of the disciples or Mary or Mary Magdelene mentioned that there were markings on the binding cloths.
And since the Word doesn’t discuss it, nor stress the importance of such an artifact, our faith shouldn’t rest on it.
Remember, even a handkerchief that had touched Paul was believed to be able to heal a woman; it would seem unlikely that Christ’s gravecloths were not discussed any further than they were discussed in the Word.