I thought that the 'Report' bit only appeared questions/answers posted after they introduced the function and it wasn't applied to anything earlier than that, hence the weird half-and-half effect on some questions.
GAB PaulB, GAB Indie, GAB brawburd! You're right Paul. Look at the 'Question and Answer' Q from paulz a couple down the list. Only brawburd's answer has the report button next to it! Very strange!
I thought that some have the report button because AB Ed hasn't seen it yet and okayed it, and the report button disappears after the editor has seen the post.