The faction-neutral trade network on Nar Shadda seems to be in disuse because of a lack of level 50 access points (who goes to Nar Shadda after 50 anyway).
It seems that the only use is transferring credits and objects between Republic and Sith alts by selling worthless objects for ridiculous sums of money and valued objects in a similar fashion, or doing this late at night for normal sums of money to avoid other players interfering.
Is this practice permissible?
Say you transferred some creds to a Republic alt, bought something on the GTN there, brought it over, marked up the price and sold it on the Empire GTN. Or used the stuff for your own character? Is that allowed? If not, since it is being used in that manner, I suggest that you either:
1. Do something to prevent this (not banning people, but for example not allowing alts to buy like they do with the Goblin Auction House in WOW, though friends still provide the service).
2. Allow more easy transfers between Sith and Rep alts (I prefer this solution)
3. Set up Hutt Cartel trade network access points in fleet, maybe in a seedy bar somewhere