I'm not sure how you go from here to "-Z must not work on stable". Most, if not all of the -Z flags, and certainly those people seem to care about in this thread, do not affect whether or how your code builds at all! They are merely diagnostic tools used during development. I really don't see how having those available would creates de-facto unwanted ecosystem stability.
I'm thinking more along the lines of if it compiles with
-Z, it will compile without.