My reading of the legal position for deferrals is as follows.

Student has seen things about their chosen uni, been sent literature, may have been top open day etc.

Student has accepted an offer for said uni. Gets the grades tomorrow. The material information about that offer will have changed. They haven't yet agreed to those changes.

Student says no and demands "repeat performance" under CRA15 when possible. RP = deferral to Sep 2021. Student asserts right to it. Uni rolls over.

Not advice you'll find anywhere that purports to offer the kind of advice that that is, by the way....