In Amalgamated Food Employees Union Local 590 v. Logan Valley Plaza, Inc., 391 U.S. 308, 88 S.Ct. 1601, 20 L.Ed.2d 603 (1968), the Supreme Court held that a privately owned shopping center was an appropriate place for the "speech" of labor union picketers. It stressed "the large-scale movement of this country's population from the cities to the suburbs that has been accompanied by the advent of the suburban shopping center ." Id. at 324, 88 S.Ct. at 1611.