I commented on this already in another thread that I saw first. My apology for bending the rules, just this once, by posting the same comment a second time in this active thread to make the point:

I'm sure my relative would appreciate her abusive ex getting his hands on her phone number. (And given past problems with third parties, I have to think this information -- speaking generally if not specifically -- is going to leak.)

You use the cell phone number as part of password recovery / identity verification (as I understand it). And then you do this?