Giving notice to the International Maritime Organization is good practice. The reason being is that there's a danger that pieces (or the booster itself) could o

Giving notice to the International Maritime Organization is good practice. The reason being is that there's a danger that pieces (or the booster itself) could or will fall into the sea, posing a danger to shipping. For example, in Florida, launches have been delayed when boats stray into the exclusion zone, and the U.S. Coast Guard assists with this. As for the legality, that's a UN question. Sovereign airspace plays a role, along with whatever UN Security Council resolutions are applicable.