My group is transitioning from 7 Days to the Grave to Escape from Old Korvosa, and I was a little disappointed to see some some of the effects of blood veil basically ignored. First, if Old Korvosa has been blockaded by the Queen, then the plague should be running rampant. It was the ward most affected by blood veil in Chapter 2, and if they are cut off from the cure the district should still be heavily infected. To counter this, I'm going to start Chapter 3 by having Cressida send the Party into Old Korvosa with diverted jugs of antidote and instructions to find Vencarlo, who will know best how to arrange for distribution. That will then lead into the rest of the chapter.
Second, in Korvosa overall, it seems unlikely that the use of currency to spread the plague would be kept under wraps. Since the Bank of Abadar doesn't know what coins are infected and how long they remain so, I would think the bank would shut down and possibly warn the population to avoid coins. The impact on commerce within the city would be devastating. While some folks might be able to resort to bartering, your average commoner probably can't do so. The economy would likely collapse, which is part of the brilliance of Rolth's and Andisain's plan. This possibility doesn't seem to be accounted for, or am I overestimating all of this?
I don't imagine the Bank of the God of Commerce would voluntarily shut itself down, nor that the city would allow it to. The economic damage of shutting down all coinage in the city would be far worse than the plague. Far more likely, they'd simply temporarily switch for foreign coinage from sources that aren't going to be infected.
While I presume Korvosa does suffer economic damage from the plague (losing even a small % of the population throws off the economy, regardless of the coinage issue), it's largely in the background (since the PCs are rich enough to likely not be over-bothered, in the same way they're very unlikely to die of disease). If you are using living expenses or the like for PCs, I highly recommend temporarily increasing the cost of it temporarily.
I think it would depend on whether or not word gets out that the plague was spread with coins. If the populace stops using coins due to fear, that's when commerce will collapse. The Bank of Abadar might have no choice but to freeze the use of currency until they can deem it safe. Even if they somehow bring in coins from neighboring countries and allow individuals to exchange Korvosan currency, it would require a massive effort that would take days or weeks. And in the interim, the Korvosan economy essentially collapses.
I'm not really thinking of this in terms of the economic impact on the PCs, but as yet another addition to the chaos in the city.
I think people will risk plague before stopping commerce altogether ("How many coins can really be tainted?", says the common man on the street). People might wash their coins, or disinfect them, or what have you, but simply stopping spending money isn't really an issue.
Try, for example, not using electronic money in modern Western society (because it's got a computer virus that will jump the species barriers, say authorities), and see how long it takes you to starve to death. Eventually the risk will start to look quite acceptable.
Ooooh, I had fun with this one.
First, I did start messing with the economy. It started with fluctuations in the price of goods: down to 75% and up to 200% and 300%. It would have gone higher but the brakes were applied before that.
I put Grandbanker Darb Tuttle in the Queen's pocket. Eventually all bank accounts were frozen, including the players', and all coinage was transferred to Castle Korvosa, "for safety" (I had to account for the treasure hoard in the Sunken Queen). All significant magic items were confiscated and the magic shops were shut down
Toward the end, gold was replaced with brass and silver with tin. Anyone coming into the city had to exchange their coins; and of course the didn't get it back so trade ground to a halt, further isolating the city.
Oh what fun playing an evil queen.