Command strips are in fact allowed.
DECORATING YOUR STATEROOM DOOR AND STATEROOM
We recognize some of our guests like to decorate their staterooms and we, too, love seeing your creative decorations. However, for safety reasons, we must ask that you abide by the following guidelines for decorating your stateroom door as well as the interior of your stateroom.
In the interest of guest and crew safety, the following stateroom decoration policies will be instituted and strictly enforced:
Decorations may consist only of fire retardant materials. Please note that items sprayed with fire retardant spray are not acceptable
Decorations may only be placed on the stateroom door and not the surrounding frame, walls or railings
You may use magnets or Command Strips but no adhesives such as tape or glue.
Over-the-door hanging organizers must hang inside the stateroom, must also be of fire retardant material and cannot damage the door
No decorations of any kind are allowed on balconies
No decorations or items may be placed over light fittings or fixtures. This may restrict the airflow and cause the item to ignite
No string lights of any kind are allowed