Spas that accept reservations but want
to decrease arrival uncertainty can involve
their customers in arrival management
(external approaches) or avoid involving
customers (internal approaches). Perhaps
the foremost internal approach is overbooking,
which is essentially unheard-of
in spas. Instead, spas have generally relied
on last-minute business to fill unexpected
openings. The primary external approach
is to shift the responsibility for arrival to
the customer by doing such things as asking
for deposits, guaranteeing reservations
with credit cards, or reminding customers
of their appointment.