I doubt very much that the person who caused the problems at Wiscon was one who would have read such a warning, or believed that it applied to him.

And the point has been made that this sort of thing looks very like the Concom covering their backs (which was the *problem* at Wiscon), rather than reassuring attendees. To me it says "Look, you might be harassed, but we've got it covered,' I don't believe that from computer salesmen, why should I believe it from a computer-salesman style warning?