Freedom of blog-speech?

This post on freedom of speech in the Chicago Herald News via Stephen Downes. Although this instance revolves around a school pupil, the issue has wider significance for those of us with non-corporate blogs. The minefield of drawing up company policies in respect of blogging is illustrated here. Where does freedom of speech end and the employee's contractual duty not to bring the employing company into disrepute begin? Does the employing company have the right to fire someone for bad-mouthing the company at a private party? In a pub? Is a blog governed by different rules? Is the issue the size of the audience? The potential for the slight to be picked up by the press or a competitor? It's a tricky one and I suspect there will be a few precedent setting cases along the way. Sadly, this young man is caught in the middle of one such situation.