Can a waiver of Fourth Amendment rights be imposed as a condition of probation in a conviction for theft of a 49 cent pen?

Both parties recognize, as did the trial court, that there exists no direct authority on the question presented. Respondents place principal reliance upon People v. Keller (1978) 76 Cal.App.3d 827, 143 [119 Cal.App.3d 389] Cal.Rptr. 184, in which the court held that a waiver of Fourth Amendment rights could not validly be imposed as a condition of probation in a conviction for theft of a 49-cent ballpoint pen. In that case the defendant pled guilty to a second offense after an unsuccessful motion to suppress evidence obtained through a search based upon the waiver; and, since the court reversed the conviction which followed upon the guilty plea, it necessarily held by implication (though without discussion) that the invalidity of the waiver vitiated the search.