In Boyd v. United States, 881 F.2d 895 (10th Cir.1989), the Court ruled that the federal government could be held liable under the Federal Tort Claims Act (FTCA) for its failure to warn swimmers in a lake of the hazards posed by boats. Boyd, 881 F.2d at 898. We agreed with the government that its lake zoning decisions constituted an exercise of discretion involving economic and social considerations. However, we found that those considerations did not apply to the decision not to warn swimmers about dangerous conditions that resulted from the decision not to zone out boats from an area. Id. at 897, 898. The Court ruled, therefore, that as in Indian Towing Co. v. United States, 350 U.S. 61, 76 S.Ct. 122, 100 L.Ed. 48 (1955), the discretionary function exception did not apply. Id. at 898.