We did it on
DCL when we had a "last minute" booking with no problems at all. When we got to the port, I told the security person we were picking up documents at port. He had our name listed that way, so no problem getting in. TOok luggage to the porter, who checked his list and gave put tags on our luggage with our cabin number (I didn't even know cabin number, but he had it on his list.) Proceeded to the "supervisor" line (as instructed). That gal was a wiz! She is so used to doing the docs that she had the right ones out of the packet in seconds. She took my ID and asked me to complete the necessary docs. By the time I finished, she was back with my KTTW card. It took no longer than any other check in, and then we were off to the boarding line.
This was the culmination of a rather frazzled week--we were to have sailed 2 weeks later, but due to a family emergency, had to move the date. It cost us a small re-ticketing fee, and DCL was truly great about the whole thing. I actually booked less than 48 hours before sailing, and had a 16 hour drive to get to the port...can you see how frazzled I was? The fraz ended when we got to the terminal. DCL had everything under control. It was essentailly no different than any other check in.