Actually, it's sort of a myth. The real issue is homogeneous-ness. They expect people to wear the interview "uniform." When someone doesn't, the interviewers get this "wellll what have we got here" thought process going.

One story of the most "interesting" interview was a tall lanky guy from NC came in wearing a tan blazer, khakis, and a regular tie with well used shoes. The interviewers were thinking well, what have we got here... The interview went extremely well and the comment was made (about the guy) if we could hire nothing but guys like him, I think this company would be lucky.

So, moral of the story, if you are just a regular joe, spring on the suit, don't leave it to chance.

I think it was FTB (the guy).