The ezmlm FAQ explains why this is not recommended.
Manuel posted the following explanation to the list on May 12, 2003.
It will stay this way because I read this:
http://www.ezmlm.org/faq-0.40/FAQ-9.html#ss9.8
and found that they're right - I can live with the fact that people have
to think twice before posting anything to the list. :) Besides, other
lists behave in the same way, too (including soekris-tech and
freebsd-small), and every better MUA has got a "Reply All" function, so
that issue is settled as far as I'm concerned.
Also see The Great Reply-to Debate in the book Producing Open Source Software.