Re: Did Picard make the right decision with the Son'a/Baku
They weren't Federation members. They colonised the world before the Federation was founded. So the Ba'ku had first claim to the then unihabiated planet. It doesn't matter that the planet would later fall within Federation space, there are no doubt many inhabiated worlds within the region of space claimed by the Federation that aren't members, can the Federation just swoop onto an inhabiated planet and take what they want?
Maybe, maybe not.
We know that two hundred years prior the Briar Patch belonged to the Klingons. If it belonged to them before the Ba'ku set down on the planet (which nothing in canon says one way or the other) and then that planet was given to the Federation for whatever reason, there would be continuous ownership of it by someone other than the Ba'ku.
Self-appointed Knight of the Abrams Table! - Thanks Marsden!