This question (Anonymous questions and Avatars) was asked two years ago. Today I experienced what the OP did - posted as "guest" on a SE, used my real email address which SE assured me would never be seen, and to my surprise my personal gravatar was used as the image which to me is as good as posting my email address.
In the original question, it's stated by @oded that the site shouldn't do that and they'd look into it. Then it's stated in another answer by @shog9 that they'd give a workflow change some consideration.
I don't want to discuss whether or not using my real address to post as a guest was a good idea (obviously it wasn't). I just want to know if either of the two solutions that were going to be looked into were. And if so, why they were both rejected.