DC is debatable since he was in the olympics, but Bisping and Gus both pass the smell test with flying colors. Also, Gus not only gets tested by USADA, he also gets tested here in Sweden by the local anti-doping commission. If he did it in the past - who knows - but by following his training you can clearly see that he loses a lot of mass as soon as camp begins, which wouldn't be the case if he was on the juice. This is the reason why the smell test is so damn important, because if you've ever done heavy cardio you know that it is next to impossible to maintain a lot of mass.