No. If the workers show up for work, but the business has no work
for them and sends them home, there is no requirement for "show-up"
pay. Workers must be paid for actual hours worked. Businesses are
not required to give prior notice of a schedule change.
Yes. Generally businesses cannot require workers to wait on the
premises without pay. Workers must be paid for all "hours worked,"
which includes time they are required to be on the premises at the
employer's request.