Facebook has apparently blocked all users from posting or commenting 'Everyone will know'. If you do that, you will get an 'Action Blocked' notification(see picture above) that will prevent you from posting the status or comment that says it's spam.
It is not a user-exclusive problem, everyone is experiencing it and it is unknown whether it is intended or a bug, as it is nearly impossible to know if 'everyone will know' can discriminate someone.
An example of a comment being blocked by Facebook that says 'Everyone will know'.
The word is spreading rapidly and more and more users are eventually finding out, so it is only a matter of time someone approaches someone from the staff of Facebook to comment on it. Stay tuned for updates on the topic, if more on the story is learned, the post will be updated.
UPDATE:
Facebook has fixed the issue by now and everyone can post 'Everyone will know' in both posts and comments now.
UPDATE:
Facebook has fixed the issue by now and everyone can post 'Everyone will know' in both posts and comments now.