Interesting theory but all over the island beach sand runs right up to someone’s patio, bedroom window, porch, bar , hotel and it’s not public property. Yes a certain amount of beach is public But there are plenty a property lines on both Dutch and French sides running across the beach that’s private land Even if it happens to be Beach sand. Examples are all over the island of buildings being built on the beach Seawalls, private porches on beaches , etc. etc. etc.