A program passed all 24 of its recorded tests and still accepted a permission record that had never been issued.
Does not establish. One defect in one program built for this study. Not a measurement of deployed systems, and no claim about how often authorisation records are treated as evidence of authorisation. Not a break-in: producing the forgery requires the ability to run code as the same user, and such an actor can edit the target directly without any record. The minimal fix establishes that a membership check closes this specific defect; it does not establish at-most-once execution, atomic consumption, or independent measurement of the effect.