On Fri, 11 Dec 2015, Rainer Weikusat wrote:

> This suggests that another 'default behaviour' is "client can't do
> threading based on References"

I think this is (together with non-text-only-mails) the main reason also
for sensible people to top-post and fully quote in typical
Outlook-/Exchange-environments.

But for me it seems really weird to have this kind of problems/discussion
also in this environment (where are those "Veteran Unix Admins" and do
they really use Outlook/Exchange these days?).