While I've been inactive with PADI for a couple years, I'm pretty sure my memory serves me in that is a standards violation. According to my PADI instructor friends, PADI has made it harder to get PICs (what is used to process certs) as they are trying to crack down on people not buying training materials (as PADI is a publishing company of books and cards). However, people are able to buy valid new materials online, so the instructor/shop has the burden of dealing with this change in policy.
Asking students to buy new training materials isn't that big of an ask. I don't think PADI's expectations of this are unreasonable. If you think that PADI books are too expensive, maybe diving isn't for you.