In what circumstances will a defendant be bound by the Court of Appeal as a result of a plea bargain?

"A defendant may admit an enhancement for a variety of reasons: as part of a plea bargain, as in People v. Jackson [ (1985) 37 Cal.3d 826, 210 Cal.Rptr. 623, 694 P.2d 736]; to obtain a perceived tactical advantage, such as keeping the convictions from the ken of the jury, as here; because he believes it futile to contest the prosecution's proof; or simply because he honestly knows the allegations to be true. We know of no cases which hold that an admission induced by a plea bargain is any more effective to prove a contested allegation than admissions induced by some other motive. To the contrary, when the sufficiency of an admission of a prior conviction is called into question, the only issue is whether the admission was voluntary, made by a defendant who has been informed of his constitutional rights and of the consequences of the admission. (See In re Yurko (1974) 10 Cal.3d 857 [112 Cal.Rptr. 513, 519 P.2d 561]....) An admission which meets those standards is binding whether or not defendant obtained an adequate consideration in return for the admission." (Id. 41 Cal.3d at pp. 844-845, 226 Cal.Rptr. 107, 718 P.2d 94.) ⁴