Bring your own zippered pillow cases and give the steward explicit instructions not to send them to the laundry. Use a laundry marker pen to write your name on them.
if you are lucky enough to find brightly colored or flowered or polka dot zippered cases, buy those to make it even easier to see that they don’t go in with the laundry.
Oh dear, on a ship you will also be told at what hour you can have breakfast in the MDR, at what hour you can see the comedian, at what hour you can swim in the pool. Pretty much everything. 😀
It is an interesting point because if those under 18 could have their elite and elite plus status, they could also have free laundry, the Wi-Fi discount, and so forth
The OP asked an interesting question but I think it is one that no one here on Cruise Critic can answer. It was a corporate decision by Celebrity made years ago and the reasons are probably lost in the mist of time. I would be surprised if anyone at Celebrity even remembers why the decision was made that way.
You have been lucky not to have been caught with an extension cord. If they do see it in your carry-on luggage as it goes through x-ray, they will probably take it. Even in your check luggage it may be confiscated. Much easier to request one from Special needs ahead of time and have it in your state room waiting for you and not risk having your luggage delayed.
On millennium Panama Canal westbound in April 2024 they used the dining room for a buffet style breakfast because there were so many elites that Tuscan would not handle the potential crowd. On the following cruise they were not so many Elites and the breakfast was moved back to Tuscan and menus were used.
always consult the instruction sheet you will find in your stateroom to see which venue they are using.