According to the Contra Times which is a newspaper out of Miami they had an article about this.
Their article sited that they could only find 2 cruiselines that would allow you to walk up and purchase a ticket last minute and that is Carnival and Costa. Three other lines --
Royal Caribbean, Princess and Holland America -- cut off their bookings 24 hours before sailing. Norwegian Cruise Line has a 48-hour deadline, Celebrity has a five-day deadline and Clipper Cruise Line, which sails the Sacramento Delta, requires that passengers book one week before leaving. A spokeswoman with Cunard Line said Cunard accepts passengers on the day of departure but only if voyages are booked through a
travel agent or by calling the cruise line directly. It does not allow walk-up passengers
Jennifer de la Cruz, a spokeswoman for Miami-based Carnival
Cruise Lines, said Carnival accepts last-minute passengers at all of its terminals, including Long Beach.
Most operators cite security precautions for their booking deadlines. Since the terrorist attacks, most operators have tightened guidelines allowing nonpassengers to get close to boarding areas. The Bureau of Customs and Border Protection, which operates under the direction of the Department of Homeland Security, allows passengers to book trips within 15 minutes of a ship's departure, but most cruise lines instituted their own deadlines.
"After 9/11, along with everybody else, we decided it's not a good idea to take walk-ups," said Greg Purdy, director of security for Royal Caribbean Cruises. "It comes down to company policy."
http://www.miami.com/mld/cctimes/living/travel/7332086.htm
*edited to add that you may have to subscribe in order to read this article! The first time I read it I did not have to but this time I did*
Also from the federal register issued in part by the DOJ and INS:
http://edocket.access.gpo.gov/2003/02-33145.htm
Electronic departure manifests. An appropriate official of
every commercial vessel or aircraft departing from the United States to any place outside of the United States shall transmit electronically to the Service a passenger departure manifest and a crewmember departure manifest. The electronic departure manifest must contain the data elements set forth in paragraph (e) of this section for each passenger
and crewmember.
(1)
An appropriate official of a commercial vessel or aircraft must transmit both the passenger departure manifest and the crewmember departure manifest to the Service no later than 15 minutes before the flight or vessel departs from the United States.
(2)
If additional passengers or crewmembers board or disembark
after the original manifest has been submitted, an appropriate official of the vessel or aircraft concerned will also be required to submit amended or updated passenger and crewmember information electronically to the Service no later than 15 minutes after the flight or vessel has departed from the United States. An appropriate official of the aircraft or vessel concerned must also notify the Service electronically if a flight or voyage has been cancelled after a departure manifest has been submitted.
(d) Electronic format.
(1) The arrival and departure manifests for passengers and
crewmember must be transmitted electronically to the Service via the USCS, by means of an electronic data interchange system that is approved by the Service.
(2) The passenger arrival and departure manifests must be
transmitted separately from the crewmember arrival and departure manifests. To distinguish the two manifests transmitted for a given flight or vessel, the crewmember arrival and departure manifests must have the alpha character ``C'' included in the transmission to denote that the manifest information pertains to the crewmembers for the flight or vessel.
This was to go into effect by January 1, 2003 and that passenger lists have to be filed no later than 15 min before the cruise departs and that if the manifest changes after the 15 min manifest has been sent they have an additional 15 min to change it after the vessel has departed.
I think it's common misconception that manifests have to be filed long before the ship leaves but from all that I can gather it's up to the cruiseline to decide their cut off policies! If you want to know what
DCL's policy is I'd suggest you just call them and ask..after all they are the experts not a bunch of us sitting at home.
Heidi