To show solidarity?
If asked by Trumpanzees and their ilk whether or not we really are Jewish we could respond with, “Would it make any difference?”
It would be futile in small numbers yet quite effective, I’d suppose, in large numbers.
Edit. An hour or so later: Didn’t the Danes do this when the Nazis made their attempt to round up the Danish Jews? I’m not sure if this is true or if this is some kind of hopeful false memory in me.
It might behoove me, and anyone else who’s interested, to look it up and refresh our memories. The Danes did manage to save all but a handful of their Jewish citizens by hiding them and smuggling them to, mostly, Sweden. One of the few inspiring chapters in the story of WWII.