I studied law, I deal with Contract law on a daily basis and under English law any extraneous clauses need to be clearly and well identified and made clear at the very start of the invitation to treat. In fact one case I vaguely remember learning was that such a clause should fly in the face so much that any reasonable man ought to be able to identify it on the outset of the negotiations period. But then came Ebay... I think the poor old victim has a very good case if he can establish a jurisdiction.
Unfortunately some people fly in the face of decency and good morality and push the boundaries of what should be legal.
When I sell on Ebay I try to make any extraneous clauses very very clear, I use asterix's different colours and put in big bold and capital letters NOTE: BAD POINTS: etc... I think Ebay need to consider including a separate section dealing with the negative sides of products.
