What is the legal test for disqualification of a witness as a consequence of a violation of an exclusion order?

Some courts have viewed disqualification of a witness as too harsh a sanction for a violation of a witness exclusion order. (See United States v. Smith (4th Cir. 2006) 441 F.3d 254, 263 ["Exclusion of a witness' testimony is 'an extreme remedy' that 'impinges upon the right to present a defense,' and thus should be employed sparingly."]; United States v. Hobbs (9th Cir. 1994) 31 F.3d 918, 922 [given "constitutionally based right of the defendant to present evidence in his favor, disqualification of defense witnesses is too

Page 63