Not long before this requirement went into place, I was held up by Labor Day traffic and road construction on the way to the Port of Norfolk.
Once finding it, I dropped off my cruise partner and our luggage and spent 30 minutes following the confused directions to the parking lot, then spent another 30 minutes waiting for the cruise bus to leave for the terminal.
Moral of the story: Don't take chances. I surely would have been left behind based on today's security regulations. It may be worth arriving a day early and overnighting to ensure you board in plenty of time.
The U.S. Department of Homeland Security requires all cruise lines to provide final passenger manifests 60 minutes prior to departure from U.S. ports.
The clock starts ticking as soon as the manifest is transmitted...all guests that are checked-in at the 60-minute mark are on the manifest and the manifest is transmitted to US Customs and Border Protection.
Which means that these late passengers have held up the entire ship by an hour. This is why you must arrive at the pier in plenty of time, to avoid being denied
Also...All cruise passengers MUST complete their Online Pre-Registration with the cruise line, no later than 6 days prior to the sail date. Anyone who fails to complete this process, will be required to provide this information at check-in at least 2 hours prior to the ship's scheduled departure, or they may be denied boarding.
East Coast Ports