from these decisions is that allegations not necessary to be proved for a conviction — in this case the overt acts — are not admitted by a plea. Any other rule would be inconsistent with the rationale underlying these decisions that “[t]he effect [of a guilty plea] is the same as if [defendant] had been tried before a jury and had been found guilty on evidence covering all of the material facts.” Davis, 452 F.2d at 578. Under the government’s argument, Alvarez-Sanchez’s guilty plea would be given greater effect than Parra Cazares’ conviction of the same offense after a jury trial. Moreover, to attribute to a defendant an admission which was never subject to a plea colloquy under Fed.R.Crim.P. 11 would undermine the rule’s prophylactic purposes. As the Court put it in McCa Cir.1988) (<HOLDING>) with United States v. Silvers, 84 F.3d 1317,
holding without citation of authority that guilty plea to indictment charging mail fraud scheme involving 135 victims precluded defendant from claiming at sentencing that fewer victims were involved holding that the first element of mail fraud  knowing participation in a scheme to defraud  can extend beyond the specific mailing and that the loss calculation for a mail fraud conviction may include any loss from the fraudulent scheme that the mailing furthered recognizing that a mailing must be sufficiently related to the fraudulent scheme to support a charge of mail fraud holding clerks action in giving requested mail fraud and contract documents to jury without consulting counsel or judge was error but defendant was not prejudiced because virtually all exhibits were either contract or mail fraud documents holding direct misrepresentations were not required for mail fraud conviction