So, Icon class, one way to potentially save some money for a couple is to book with two fake kids and then cancel them (no fear of being moved or repriced I assume)?
It may look like that especially on "regular" 7 day runs from the same home port since they almost never change but unlikely to be true when the current sailing and the future sailing are of different durations/home ports (menu might change a bit for non-US departures).
The thing is, if you look hard enough you can probably find stuff like that even on Oasis.
Again, if wear and tear is a criterion for cruising, don't book anything more than about a 3–4-year-old ship.
Probably never. Well over 100% sure or even 110%, but filling every berth would very tough - out of 6000+ customers, someone is bound to miss the sailing.
Maybe - some reports indicate that RCI may contact the TA directly to ascertain the issue (once you claim they are unresponsive). As mentioned, you can also ask the TA to simply pass the booking to RCI.
Very rarely are there any sales on board. If you are D and up, you'd have to do the math to see if buying in advance is better than using your discount on board.
That is an RCI IT issue and has no bearing on what happens at the pier. I bet you a D drink that if you didn't check in online and go to the pier with just the passport the check in agent won't even notice the expiration date and won't say anything about it.