What is the current state of the law on due process when it comes to the exclusion of evidence of a pretrial identification "infected by improper police influence"?

Due process requires that evidence of a pretrial identification "infected by improper police influence" be screened by a trial court and excluded if the court determines "there is 'a very substantial likelihood of irreparable misidentification,' [citation]." (Perry v. New Hampshire (2012) _ U.S. _, _ [132 S.Ct. 716, 720] (Perry).) "[I]f the indicia of reliability are strong enough to outweigh the corrupting effect of the police-arranged suggestive circumstances, the identification evidence ordinarily will be admitted, and the jury will ultimately determine its worth." (Ibid.) But the introduction of purportedly unreliable identification evidence does not violate due process "when the identification was not procured under unnecessarily suggestive circumstances arranged by law enforcement." (Id. at p. 730.) "When no improper law enforcement activity is involved, . . . it suffices to test reliability through the rights and opportunities generally designed for that purpose, notably, the presence of counsel at postindictment lineups, vigorous cross-examination, protective rules of evidence, and jury instructions on both the fallibility of eyewitness identification and the requirement that guilt be proved beyond a reasonable doubt." (Id. at p. 721.)