It's an interesting story. First, I'll tell you what I think I would have done. First, enjoy it as long as I found it fun and enjoyable. Second, say, "I'm not enjoying this any more at all." If that had no effect, say "If you don't stop by the time I count to ten, I'm going to hang up." Count to ten. If she doesn't stop, say "bye" and hang up.

Make no aspersions on her character. But set a limit based on something you can carry it out, a limit she can comply with if she wants, and then if needed carry it out. Pretty trivial as parenting situations go, really. Even Renee can hang up and if nothing else watch the second hand go around until the babysitting gig is over. But parents can't hang up.

And this gets to my skepticism about strong forms of youth liberation. You can't reason your way out of all such situations, even with 7-year-olds (let alone 4-year-olds). And as most parents lack infinite time and patience, there are times where "Because I said so" is a reasonable answer (or "I can't explain that right now" if you want the slightly more polite variant). When used within reason, kids accept that. Of course you can hope for a big-picture plan where you do in fact listen carefully to your kid and explain the, well, big picture. But living up to that requires insight and is hard work. So while I personally cringe when I see parents being gruff or insensitive, I'm slow to judge them.

I also don't think there is a good explanation for why you won't let your 10-year-old son intentionally belch at the table endlessly without consequences. You can argue that such a prohibition is culturally specific (and he will make what boils down to that argument himself). But we live in the culture we do. And some of the time that means parents are making rules that are in some grand sense arbitrary. It can of course be overdone, but at root it is part of good parenting.