CC used to be the gold standard for the most tuned in cruisers, and RC recognized it.
Now there are plenty of other options for the hard core cruisers while CC sees plenty of others that are new cruisers or not cruisers at all.
That loyalty boost that CC used to have that RC wanted to keep a line into is watered down enough that the M&M is just thing of the past.
Week long vacations are a pretty rare thing in the USA compared to other western countries. In the UK and Europe, you're encouraged and even expected to take a long vacation. In the USA, many are outright discouraged from doing so.
Remember that 48 hour window is based on midnight on the day your cruise leaves. So if your cruise leaves on a Saturday, Wednesday at 11:59pm local to the homeport is your deadline
One of two things would happen. 1) People change their minds once they board and see menu and show schedules and want to change their reservations. Or 2) People forget they even booked a given night and no-show.
They'll have shuttles circling the lots to take you back to the rental car place. Though I don't know for sure the frequency and/or if you are better off calling them when you get off the ship.
We always rent a car for the one-way trip to Orlando. The drop off and shuttle is very convenient and well run for Enterprise. With so many people renting cars when coming off a ship, the price is rarely more than a traditional round trip rental.
Then take GoPort for the return trip.