Employees at Southwest Motor became suspicious of two fifty-five gallon drums. They were labeled as phosphoric acid, but they were too light to contain acid. They did not make sloshing noises when moved and lacked the hazardous materials labels normally required for such freight. The informed customs and two agents arrived. The weight listed on the order was less than half the expected. A drug-sniffing dog alerted to the drums. They opened the drums without obtaining a warrant and discovered marijuana inside. They resealed the drum and set up a sting. Villarreal and Gonzales (Ds) paid two employees of South Texas Recycling to pick up the drums for them and gave them the receipt for the drums. Ds followed in Villarreal's red pick-up truck. Torres and Guzman went back to their work location and then loaded the drums from the flatbed into the pick-up. Ds were arrested shortly thereafter, and the drums were seized. Ds were charged with possessing and conspiring to possess more than 100 kilograms of marijuana with intent to distribute it in violation of 21 U.S.C. §§ 841(a)(1), 841(b)(1)(B) and 846. At a pre-trial suppression hearing, Ds argued that the warrantless search of the drum violated their Fourth Amendment rights. P contended that Ds had no reasonable expectation of privacy in the drums and that the customs agents had, in any event, obtained consent to search them. The district court rejected P's arguments and granted Ds the motion to suppress. P appealed.