Most cruiselines employ a cruise card system.
This plastic card is
a means of tracking passenger
embarkation or disembarkation during port stay,
a key to enter staterooms,
and an on board credit card.
Carnival Cruises also uses their cruise card
as a status symbol.
New cruisers are blue.
Returning passengers have gold
or platinum (10 plus cruises) cards.
Staff makes an extra fuss
over the gold and platinum card holders
but more importantly,
other cruisers notice.
They notice, they ask questions,
they want one.
The only way to get one
is to book another cruise
with the same cruiseline.