When criminal cases are set for trial, are both parties the defendant and the prosecutor/DA obligated to give a proper witness list including key eye witnesses, experts, all of them? Can the DA play the game of disclosing some key witness in the end as a part of cunning strategy? I really want to know how blatantly the DA can violate this policy. Everyone knows of Brady issues but DAs ignore that at times or do not pay enough attention. For the witness list also they can surprise right at the spot during the trial as well?