(concurring):
I favored meeting the retroactivity issue during our adjudication of United States ex rel. Matthews v. Johnson, 503 F .2d 339 (3d Cir. 1974) (in banc), cert. denied, 420 U.S. 952, 95 S.Ct. 1336, 43 L.Ed.2d 430 (1975), and, at that point, would have followed the limitations set forth in United States v. Zirpolo, 450 F.2d 424, 431-33 (3d Cir. 1971). In the interim since the Matthews opinion was filed, the Supreme Court decided Daniel v. Louisiana, 420 U.S. 31, 95 S.Ct. 751, 42 L.Ed.2d 766 (1975), which was concerned with essentially the same issue as Zirpolo. Daniel held that retroactivity was not required as to trial procedures which occurred before the date of the decision. The same standard should apply in this case, and I, therefore, join in the majority opinion.