Geof, I dispute that the fax requirement is benficial. As far as I’m concerned, it’s unnecessary and a pain. Other affiliates may disagree but I do not find it beneficial in any way. If it was such a great benefit then everyone else would require it – whereas next to no-one does.
I suggest you add information to the affiliate cashier page to state that docs can be scanned/e-mailed as there is no mention of this anywhere.