Karen, you are right on, as usual.
Some of us just can't wait to get on the ship and maximize our time. Although it depends what you're doing prior to boarding--if you were somewhere with lots to do, I could easily imagine boarding later.
But for our first non-PG cruise (you can't really board before 3 there), we took the advice to appear around 12-1. We couldn't wait to explore the ship and revel in our good judgement in booking such a great cruise!
