"They" being Ekfe (MACO). I mentioned the data sheet in the preceding sentence, therefore "they" clearly referred to the publishers of the data sheet. The data sheet says that based on testing, exposure of 35mm cassettes to ambient light is worse than having the cassettes scanned by carry-on x-ray machines.
"Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."