The last two passenger liners that I sailed in between 1979 and 1992 were practically unrestricted as far as the passengers went. If they wanted to go up to the bow at sea, they could do as long as the weather was OK. If they wanted to wander around the bridge at sea, they could do, and talk with the officer of the watch. If they wanted to visit the engineroom, the chief engineer would oblige on request. They could visit officers in their cabins and officers could visit them in theirs. It was all rather wonderful, but the were very small ships, about 300 feet long, the first one being about 3,000 tons (76 passangers) and the 2nd one 6,000 tons (132 passengers) on the run between Avonmouth (Bristol) and Cape Town via Tenerife, Ascension Island and St. Helena Island!
We had regular passengers that came back year after year and who said they would never sail in a large passenger ship again, because they preferred the comfortable intimacy of the microscopic RMS ST. HELENA!

Passengers would never be allowed that freedom in modern giants!
It makes me laugh

when I hear people say the TITANIC is too small at 46,329 gross tons I found the old RMS WINDSOR CASTLE mind boggling in its sheer size when I first joined - a mere 37,640 gross tons!
The proposed replica is already drifting away from what the original was like. The have deceided to build it with flat hull, to save money. The original had a sheer (a curve along the hull). Also, it is to have an extra deck with modern lifeboats, so already it will look only superficially like the original!
Bob