So this is a specific case, but the bottom line is: How bad could/should it get?
Here are the details:
One of the PC's started with a "Bounty" Obligation owed to Durga the Hutt, but that PC bought off that debt. No worries. (right)? There are hard feelings but some of the PC's former contacts are sympathetic.
Meanwhile the PC's were approached by a new Hutt (we'll call her Soshu and no she's not cannon but) she's affiliated with the Gorensla Kajidic and is the heir apparent for Oruba's operations. Oruba's seat on the council has been left vacant, for the time being, and Soshu is trying to angle to get onto that seat.
To that end, Soshu hired the PC's to make a delivery to Roon, which they accepted. As a side quest, Soshu asked the aforementioned PC (let's call her Silver because that's her callsign) to also remove a former friend "from the game board." Soshu was clear that she didn't mean for Silver to kill her friend, but to have that person stop working for Durga.
Meanwhile Durga has been trying to stage a coup d'etat on Roon to remove an uncooperative and overly independent Governor.
And Soshu is shipping cash & weapons to prop up the Governor. The other thing that Soshu does, is present evidence to Durga that Silver's friend has been less than diligent in some of her operations to the point of betrayal, AFTER the PC's leave Nar Shaddaa.
Long story short, the PC's deliver the (unknown to them) cargo, don't directly involve themselves in the coup, but are affected on the periphery.
Plus a group of Mando bounty hunters show up and ask after's Silver's friend. The Mando's were hired by Durga and also claim that they received intel from Soshu that Silver would be able to 'help' them collect on the bounty.
No big deal. Right?
Well, the players have been too Roon before on a 'rescue the princess' plot and have made contact with some of the locals. In the midst of all of this excitement, the PC's drop by to talk to their local farmer contact and offer to buy up a shipload of 'spice.' (And we're not talking about the Tabasco variety of spice).
Negotiations take a bit of time to coordinate but the locals come through and sell the spice directly to the PC's for cash. (Their contact acts as a broker for his neighbors and the PC's purchase 175 EC of unprocessed spice). I'm figuring that this haul qualifies for about 20% of Roon's production of this product for this season. 20% that both the Governor AND Durga will sorely miss . . .
The PC's return to Nar Shaddaa to get paid by Soshu (but neglect to let her know about their 'side' venture).
In selling the lot of spice, the PC's use their streetwise to try to find a buyer. They end up talking to Triloc (a former client of the group) and though she doesn't handle that kind of product, she refers them to a cousin of hers on Tatooine.
They eventually negotiate and sell their batch to Jabba and (they think) they walk away with a handsome profit (which they kinda do actually). One of the concerns that both Triloc and Jabba express is the concern over where this product came from and how the PC's came about this lot. I'm guessing that this much spice constitutes about 4-12% of the annual Ryloth Spice produced in the Galaxy. So it's not an inconsiderable sum.
So that sums up the case study.
The question is: How badly are the various Hutts going to take this little surprise? And we can count on this being a disappointment for the Twi'lek Governor on Roon too.
Whatever could they do?