I think it is a good idea, there are certain aspects of Sosua that just can not, will not and shouldn't be changed, but any effort to improve the security and safety of the place should be welcomed rather than ditched before it even gets going. Anything at all to give tourists a bit of reasurrance after recent times is a good thing, it gets a bad rap for nothing less than being a tourist town, dealing with things that every other tourist town in the world has to deal with.
I give security cameras a thumbs up!!