A warning or caution of some sort should be added to the email notifications, that replies to these notifications will end up as public forum posts that may include the sender's email address and other private information from an appended signature.
Just like the author of the thread in the link, I found by accident in another forum (non Adobe related) a similar danger, which I'll describe here just in case something similar happens in these forums.
In that other forum, participants can choose to be contacted only by private messages, or also by email. If one tries to send a PM to one of the very few who have chosen the latter, one gets a message box that offers the option to do it by email or by PM, with a tiny warning at the bottom of the page that if one chooses the email way, one's email address will be made known to the recipient. As I wasn't aware of this, I must have chosen the email option, without noticing the almost invisible warning at the bottom of the page. I couldn't believe my eyes when that person replied to my private email address. And it took me and the team in charge of the forums a couple of days to find out what had happened. At my request, the warning was moved to a position where it cannot be ignored, and changed to a larger and bolded typeface in red.
Message was edited by: Claudio González. Reason: improving the language.