The United States Supreme Court originally stated that employees
subject to the act must be paid for all time spent in ``physical or
mental exertion (whether burdensome or not) controlled or required by
the employer and pursued necessarily and primarily for the benefit of
the employer of his business.'' (Tennessee Coal, Iron & Railroad Co. v.
Muscoda Local No. 123, 321 U. S. 590 (1944)) Subsequently, the Court
ruled that there need be no exertion at all and that all hours are hours
worked which the employee is required to give his employer, 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.'' (Armour & Co. v. Wantock, 323
U.S. 126 (1944); Skidmore v. Swift, 323 U.S. 134 (1944)) The workweek
ordinarily includes ``all the time during which an employee is
necessarily required to be on the employer's premises, on duty or at a
prescribed work place''. (Anderson v. Mt. Clemens Pottery Co., 328 U.S.
680 (1946)) The Portal-to-Portal Act did not change the rule except to
provide an exception for preliminary and postliminary activities. See
Sec. 785.34.