Yes, this group all have priority to check in and wait to board. That was our experience sailing in a NS on the Koningsdam last year. Once boarding commences, it will literally be by row after row of people who are waiting, with those with priority starting first. The priority is to board a few minutes prior to everyone else, or however long it takes for people in the queue to be scanned while boarding. They try their best to conduct the boarding so everyone is actually moving through the terminal and on the gangplank and when they reach the actual ship it is scan on and step aboard and move forward for everyone else.