Re: Next Case...
Great detailed breakdown of the problem.
She's not an idiot - it was (is?) a real problem. I have family members who experienced it when one member had to start using a Windows Phone for work reasons, and everyone else's iPhones remembered them as being on iMessage.
Apple really screwed up this experience
(Informed opinion from mobile developer with 30+ years experience who struggled to explain how this problem happened and what Apple were thinking).