Great Debate: Phones in the potty?

The other day I was in the restroom at a restaurant and heard the woman in the next stall talking.
And not to me.
She was, I figured out, talking on her cell phone.
It was such a strange experience — even for me as an innocent participant in this. I mean, I didn’t want to flush for fear of “outing” this woman, who was casually chatting on her iPhone like she was lounging in her living room.
I’ll admit: I’ve walked into the bathroom still on the phone. But I wouldn’t go into full restroom action with someone on the other end listening. That’s just rude — and gross.
But why? We don’t seem to mind people talking in restrooms. Why is it different if that conversation is taking place on a mobile device?
Probably because we suspect the person on the other end doesn’t know where the caller is — or what those strange sounds are. And we feel awkward, not just for us, but for that unsuspecting person on the line.
The bathroom should be a private space — even if it’s a public restroom. I’m not going to subject others to my bathroom antics — and neither should you.
What do you think?