Clubba Hubba - S1-E3
Continuity mistake: As Carlton and Will battle out with their "I bet he won't", "I bet he will", Will is holding his drink with his left hand. When he breaks the fourth wall with a joke in a new shot, the glass switches hands. (00:05:00)
Answer: Because Carlton is naive, trusting, and optimistic. He lived a pretty sheltered life in Bel-Air and just doesn't think police officers would do anything unjust. At this point in his life, he just hasn't gone through the things Will has to make him think otherwise.
Bishop73