It seems to me you may not understand how cross-posting works.

I believe I do. However, newsreaders often don't. Some newsreaders
(I've been stuck with them sometimes) will only post to the newsgroup
from which the reply was made, and ignore the rest of the crossposting.
Some newsreaders will present crossposted messages as new, even if
they have been read in a different thread. Some newsreaders can be set
to send replies to places other than the originating newsgroup, and
other newsreaders are unable to detect this and defend against it.

I don't know what newsreader any individual will be using.

Jose
--
Quantum Mechanics is like this: God =does= play dice with the universe,
except there's no God, and there's no dice. And maybe there's no universe.
for Email, make the obvious change in the address.