I do sympathize with Migdia and, particularly as a new participant in WMF projects, it probably did not occur to her that communication related to most aspects of most projects is public by default.
 
At the same time, it does seem to be clear that there was public access to archives at least.
 
If I may suggest, several of the interface statements including pages where one requests posting access and the email confirming subscription should probably emphasize that this mailing list is publicly available, may be mirrored on other sites, and any posts a person makes will be searchable on most major search engines.  I'd encourage stating bluntly that once a post is made, it should be considered to be publicly and widely available on the internet, and that it will not be deleted or removed. 
 
At the same time, I'd like to encourage everyone on the list to give serious thought to actively trimming your posts, limiting inclusion to only the segments of posts you're responding to rather than a long chain of prior posts.  (Yes, I'm probably as guilty as anyone else on this point.)  If nothing else, it's good mailing list etiquette, and reduces the number of posts that are bounced to the moderation queue because of length. 
 
Best,
 
Risker