Well, play it out if you said something. What would happen? Do you fear that it will escalate to physical violence? Or are you just afraid that they won't care that you said something to them?
No, I'm afraid that they *will* care, in that they'll be pleased that what they're trying to do - upset us both - has succeeded. I think that as a result they'd do it more and for longer.
That was my experience when I or anyone else tried to stand up for me, and I'm afraid that both here and on another forum where I asked for advice, everyone who's ever had this happen to them has said Ignore. Various people have said "say something" on principle, but nobody (yet!) has said "it happened to me, or to my child, and someone said something and it stopped".
