I don't think that was the point of her statement. I think she was basically saying "At least before, the booth babes were obvious, and other women were assumed to be engineers who belonged there for their technical merits. Now, companies are sending attractive, non-technical female product promoters and others outside of the engineering field dressed in street clothes. Now, it is harder to tell which women are engineers and which are PR/marketing/booth babes/whatever." Seems a valid observation, though I think the real issue is that women need to vet themselves as engineers at all, while it is assumed that men at a conference are technical unless proven otherwise.