Boss Hog, please can you explain to me why, if you and others find this type of thread so offensive, do you not screen/remove it quickly from the forum. It seems the only reason why you allow it to stay up is so you and others can come up with 'witty' responses, some of which seem to come under the 'vulgar' category that supposedly is frowned upon. I am sure the person who put up the original post didn't mean to offend, indeed she seemed to target students who might well be interested in this type of work. If she did mean to offend then surely the better response would have been to remove the post.
Just so you know, I am Creative Director for a London agency and understand full well the frustration of people expecting unpaid work. However as 'free' pitches are still very much part of our industry it will be something that will continue to frustrate for some time. A more mature response will do our industry far more than a sarcastic remark, and hopefully not scare off people looking to designers for help in the future. Rant over.