Where judges can flex their discretionary muscle, however, is under Rule 20(b). Rule 20(b) states that even if the Rule 20(a)(2) conditions are met, the court may order separate trials to protect
against “embarrassment, delay, expense, or other prejudice . . . .”151Judge Baylson, presiding in the Eastern District of Pennsylvania,neatly summarized the various reasons courts have given for denying
joinder of Doe defendants in BitTorrent cases: