Isn't Kodachrome trickier to scan? For instance the normal IR dust-removal trick won't work because of the physical construction of the film? Or maybe they'd blur out any slide because they're scanning it with a crummy flatbed scanner, or taking a picture of it against a lightbox with their digital camera, or something. I've got some old Kodachrome and Ektachrome slides my grandfather shot 40 years ago and they're quite sharp!