Does the fact that a would-be bank robber's sister-in-law has the keys to the vault preclude him from a reduction?

Many pre-existing circumstances may doom a conspiracy, without rendering the conspirators any less culpable for their acts. In Chapdelaine, a scheduling miscalculation rendered it impossible for the conspirators to accomplish their heist because the armored truck had long departed; yet the conspirators, having arrived at the scene bearing guns, disguises and other instruments of crime, were not entitled to a reduction. Id. at 35-36. In United States v. Toles, 867 F.2d 222, 223 (5th Cir.1989), a would-be bank robber, having demanded money from a teller under threat of physical violence, was not entitled to a reduction simply because the teller never had the keys to the bank vault. In Halmos v. United States, 872 F.Supp. 762, 766 (D.Hawaii 1995), an armed robber fled after realizing that the bank teller from whom he had just demanded money ("or you will die") happened to be his sister-in-law; that the perpetrator was bound to be identified by a relative in the bank did not entitle him to a reduction.