Just had another thought on what might have happened... if she had started with what she thought was a full bolt and based her "number available" on the yardage printed on the bolt... well, we're frequently finding that we come up a half-yard to 3/4-yard short on our bolts. Meaning that there isn't quite as much on them as the manufacturer states. But it isn't worth the bother of unrolling and measuring them all... so we just sigh and move on.

I would agree. Maybe someone who works for this person made the decision, not thinking about the problem it could create. I would let them know in a private e mail that it would have been better to contact you first. That way, the owner will have the option of handling it or changing her policy.