If someone does something that another person does not approve of, or said person makes a comment against a popular trend or the consensus of a majority, the opinion or credibility of that person may simply be thrown out by stating that they "wear sketchers," implying that they are not in a position to make a proper judgment on the particular subject being discussed.
Person 1: "Hey, did you hear Jim today? He said that the BCS system is fine the way it is!"
Person 2: "Nah, man, he's a fool. That clown wears sketchers."