I live in Florida. This sounds very much like our condo commandos down here. All doors must be the same! Decorating the door is a fun part of cruising! Nothing wrong with being a little creative, as long as it doesnt damage the door permanantly. And it really does help assisting in finding your room, especially if you've had a little too much to drink.
This would be a good topic for the "cruise gripes" forum, perhaps.