You mean like, out planting corals from hobbyist captive care? Well, first of all, its a gigantic ecological disaster waiting to happen. There are many species we mix from different areas of the world, containing different diseases and parasites from different parts of the world and we would be potentially (likely) introducing a whole host of things to the environment that should never ever be there. Even something as seemingly benign as a majano anemone or a vermetid snail, unknowingly introduced to the wrong area from a different area, could totally destroy the local habitat.
When public aquariums and research facilities participate in projects where corals are held to be reintroduced to the wild, there are strict, standardized, quarantine and biosecurity measures in place to ensure nothing from other systems can be cross contaminated into the holding system.