Note: I have read What are the rules governing display names and avatars? which was entirely focused on pretending to be a specific real-life person.
On a site I use regularly, a user has a profile picture that looks like part of an autogenerated gravatar with an orange diamond in the rightmost portion of the picture. As a result when this user posts, that diamond appears before their name. I know that when real moderators post, an orange diamond appears after their name, so I wasn't fooled, but I did take a moment to look through the top users on this site to confirm that there hadn't been some recent display changes.
(rep and badges redacted, but note 1k-10k rep, no gold badges) Please don't work out the site from the badge symbol and go make this about who this user is or what this user does. I'm asking about the general concept and only included the image to forestall "or it didn't happen."
Is this ok? I have no idea whether the user is just trying to be funny, or thinks there will be fewer downvotes or close votes if they're perceived to be a moderator, or thinks their comments (which don't display pictures) will have more effect, or what. In the absence of any information about motivation, would you flag a profile picture like this? What would a moderator be likely to do in response to such a flag?