No they don't! But they should! On my Enchantment cruise the weather was not good there where a few gals wishing there was a tanning bed or a spray tan specialist onboard. These gals did not want to go home all pale like they were never on vacation.
I did a Spray Tan a few cruises ago the day before departure. The spray tan does not last a full week. But it does look great for about 4 days. You can also use a self tanner on the ship every nite before bed that helps to extend the life of the spray tan.