Our last cruise out of Charleston, our adult sons went with us and had their own cabin. They are Gold we are Platinum, we just decided to go in line with them. But what was funny was the people standing in front of us had an arrival time of 2:30pm yet it was 11am and there they were. So guess it depends on the port as well, not sure how strictly 'rules' are enforced.
The one thing I was told at guest services was concerning the tenders(water shuttle) they were able to go with us to the meeting point and get on with us, same with debarkation. They also told me that we 'should' have been able to board at the same time, considering we traveled together and were family. But where do they draw the line then, a bus load of people could be family and they traveled together, one persons status gets everyone the status ?