What is the test for abuse of trust enhancement?

"We review de novo the district court's application of the abuse of trust enhancement." United States v. Cuff, 999 F.2d 1396, 1397 n. 1 (9th Cir.1993) (per curiam). Whether a person occupies a position of trust depends upon " 'the extent to which the position provides the freedom to commit a difficult-to-detect wrong.' " Id. at 1397 (quoting United States v. Hill, 915 F.2d 502, 506 (9th Cir.1990)). The court must consider the trustor's inability to objectively and expediently determine the trustee's honesty, and the ease with which the trustor can observe the trustee's activities. See United States v. Ferrin, 994 F.2d 658, 665 (9th Cir.1993).