How have courts dealt with allegations of juror misconduct?

solely on the evidence before it and a trial judge ever watchful to prevent prejudicial occurrences and to determine the effect of such occurrences when they happen. Id. Although it is generally preferred that a trial court hold an evidentiary hearing when allegations of juror misconduct arise, it is not always required, particularly when the court knows the exact scope and nature of the misconduct. See United States v. Halbert, 712 F.2d 388, 389 (9^th Cir.1983); United States v. Hendrix, 549 F.2d 1225, 1227 (9^th Cir.1977); see also United States v. McVeigh, 153 F.3d 1166, 1187 (10th Cir.1998).