A lot of people who log that IP address think that if they needed to, there'd by a way to find out 'who left the comment', which in their world means an LJ username. Or, they're asking about activating the feature because that's what they'd like to do.
So I think somewhere near the top of that FAQ, we should state "No pony for you." Perhaps either at the end of the first paragraph or the beginning of the second.