VATICAN CITY - Pilgrims and tourists flocked to the Vatican ahead of Good Friday ceremonies as the Catholic church defends itself against accusations that Pope Benedict XVI played a role in covering up sex abuse cases.The pope was scheduled to preside over a prayer service and listen to reflections from the papal household preacher in St. Peter's Basilica on Friday evening.Hours later, thousands of faithful Catholics, clutching candles and prayer books, were expected to gather at the Colosseum to see the pope at night during at the traditional Way of the Cross procession commemorating Christ's crucifixion....