The Border planets are near enough to the central planets that they have business dealings with those on the Core. However, the Border planets are far enough away from the Core that the eyes of the Alliance can't always make out what's going on.
Thus, these planets are excellent locales for certain unscrupulous folk from the Core to conduct business dealings "in private." They don't have to move to these planets (Though there are those eccentrics who travel here from the Core to 'get away from it all' - the kind of people who build strong fortresses to keep out the riffraff, and would never dream of socializing with the local yokels). The irony is that these same folk are all in favor of the rules and regulations that govern business dealings throughout the systems - just as long as those rules and regulations don't affect them.
To give the folk on these planets credit where credits are due, there are plenty on the Border worlds who are eager to do business with those on the Core. And there are always countless numbers without a silver in their pocket here looking for work.
Landing on Beaumonde and Persephone is supposedly regulated, but the traffic is so heavy that the harried Alliance officials who try to police it have mostly thrown up their hands in frustration and sometimes don't even bother to ask what your business is (Perhaps they figure it's best they don't know!). Landing on Bellerophon is more difficult, since the world is basically off limits to all who don't own one of its elegant estates. Still, there are ways...
The Border planets are the best and worst of all possible worlds. Tall, elegant skyscrapers and magnificent mansions stare down their steel noses at cardboard hovels and crowded slums. You can buy anything on the Border planets, from someone to pick off your worst enemy to a pink ruffled dress that looks like a layer cake. (Just don't buy the 'Good Dogs' from the vendor in the Eavestown Docks. Not if you care that the sausage inside the bun was once actually a good little dog.)