Just as a friendly note: Security will do walks around the hotel occasionally and if a room-sign is offensive or otherwise inappropriate for public, we'll remove it carefully and hand it back to the owner with a friendly word. :3
Generally room signs are a great thing about a convention and at EF, security actually awards a price for the coolest door sign! Just make sure that you don't use suggestive/adult imagery and use only blue-/white-tac please. :3
We're looking forward to your creative door decorations!