In one of the episodes that remain for Sacha Baron Cohen’s latest disguised-correspondent prank exercise, among his targets is Sarah Palin, whom he interviewed in the guise of one of his new show’s alter ego characters, Billy Wayne Ruddick Jr., Ph.D. (pictured). Palin already has complained, charging that Cohen duped her by pretending to be a wounded military veteran. Cohen has countered that his Ruddick character was in a motorized scooter (not, as Palin recounted, a wheelchair), an