ORIGINAL: strykerpsg
I disagree it not making sense to house missiles in a building. Given the potential for nations to overfly the islands with prying electronic eyes, strong tropical storms and overall surrounded by very corrosive salt water spray and rain, it stands to reason that it's far cheaper to set up a shelter with a sliding roof to protect their investment.
Then, there's always the "deniability" of the militarization of the islands themselves, not to mention the legality of even building them in the first place.
If that is for launching missiles without the external sensor suite for guidance (especially ASBM), the openable roof could make sense. SAM cannot operate without any targeting, and babysitting with a warship nearby isn't economical either.
Unless, if they have mentioned the weather resistant radome on the island to act as SAM's searcher and FCR, that would be possible. My only question is the methodology of missile stockpiling: be it more concealable and make smaller targets with silos, or using hangers for mobile SAM like S-300/400 and HQ-9 to come out when deployment is needed.
Legal or not, I am afraid it have to be ultimately solved with under the strength of global orders. The Cold War is over, but nukes is still talks louder than pens, and so does the missiles and carriers. It only matter with the interest, hence the post-Tribunal Philippine with her new president. One thing for sure is, both US and China did their intention to make SCS very popular, and they both have reason to expand military actions.