I can't even think of something I'd say in a case like
that, I'd be too shocked! What I'd LIKE to do is get all animated
like with flinging my arms around and do some baby-babble of my
own where she couldn't understand me and hopefully she'd end
up feeling foolish and being the one to rush away instead of an
embarrassed me.

I'd also like to say "Wow, I REALLY pity any children YOU ever
raised!" but I doubt I'd have the nerve.