Is "bzr push" safe?

[Patrick Doyle]

I apologize that my question may be somewhat provocative, but I'm
trying to learn what I can learn about Bazaar and I came across the
"BzrForEmacsDevs" wiki page
(http://www.emacswiki.org/emacs/BzrForEmacsDevs) which states:

It might occur to you to save some effort by just doing bzr push
directly to the upstream master from inside the TASKNAME branch:

      cd $DEVHOME/emacs/TASKNAME
      bzr push bzr+ssh://USERNAME@bzr.savannah.gnu.org/emacs/trunk/

Do not do this — it can cause history to be displayed in a strange way
in the upstream master, any mirrors or branches of it, and your own
branch later. Search for the word “hidden” in this mail for more
details.

The "this mail" referenced on that page can be found at
http://lists.gnu.org/archive/html/emacs-devel/2009-11/msg01021.html

The gist (as I understand it) is that doing a "bzr push" can mess up
the commit history on the mainline development branch.

I'd like to assume that this is old and outdated advice (especially
since it is from 2009!) but I hate that word "assume", so I figured
I'd just ask the question...

Was this a problem at sometime in the past that has since been fixed?
If I'm using a modern 2.x bzr, will I have to worry about this?

Thanks for listening.

--wpd