Armour & Co. v. Wantock
In Armour & Co. v. Wantock, 323 US 126 (1944), plaintiffs were fireguards who were required to remain on the employer's premises for 24-hour shifts.
The plaintiffs in Armour were paid for their daytime hours but were not paid for their nighttime hours when they were subject to call but were allowed to spend these hours sleeping or for recreation (id. at 126).
The Court found that under the arrangement between the employer and the fireguards, the nighttime hours were working time and should be compensated (id. at 134).
The Court further stated that "an employer, if he chooses, may hire a man to do nothing, or to do nothing but wait for something to happen. Refraining from other activity often is a factor of instant readiness to serve, and idleness plays a part in all employments in a stand-by capacity. Readiness to serve may be hired, quite as much as service itself, and time spent lying in wait for threats to the safety of the employer's property may be treated by the parties as a benefit to the employer. Whether time is spent predominantly for the employer's benefit or for the employee's is a question dependent upon all the circumstances of the case" (id. at 133).
The Court in Armour found that the fireguards' presence on the employer's premises was primarily for the benefit of the employer because the fireguards were hired to protect the employer's premises from threats of fire and to perform other minor duties throughout the night (id. at 134).
Regardless of whether the fireguards spent most of their time sleeping or otherwise amusing themselves, they were still considered on duty (id.).