Now that we have a castle, I shall point out that..:
The castle is a roleplaying area by default.
This excludes possible sieges.
You don't have to participate in roleplaying when visiting the castle, but you may expect to be noticed in case there are other players around and roleplaying. You may either ignore them in such a case, or maybe announce in a roleplaying manner that you are too busy to stop to chat.
So basically, don't get too confused if the castle is full of people using /s and sounding insane. Resort to the guild chat channel if you want to talk out of character.
Looking forward to meeting you in the castle!