You cant see some of the castles when you first spawn, does this mean they should all be made visible so you know where to go? Does this mean the banners should be facing the spawn so you can see which castle is which? Of course not. It doesn't matter if the entrance is hidden, what matters is people will eventually find it if they decide to explore, and when they do their reward will be there. Otherwise there should just be a stash of weapons where you spawn... which is not such a good idea.