It happened to my friend. This is a true story.
So two of my friends were taking the MCAT at the same location. One of them was dressed up in an Armani suit and the other was wearing Nike shorts and a hanes white tee. Well, as luck would have it, the ADCOMs showed up at the testing site.
My friend panicked. He realized he wasn't dressed appropriately for the MCAT. He hoped the random drawing wouldn't pick his name, or he would kick himself for the rest of his life. Well, his name was picked. The ADCOMs (I believe they were from some small school in Boston; Harvard or something) took one look at him, and walked away. The guy in the Armani suit got an interview. He blew them away. They didn't even make him take his exam.
Be careful. Whatever you decide to wear, make sure you think long and hard about it, and ask SDN and your friends for opinions. Ask your family members as well. It is a really big deal.