I mean, cartels have been pumped up to pretty ridiculous heights by the war on drugs but it's not at the point where it would be realistic to have them say "here is a list of a few hundred usernames from SilkRoad spread out all over North America. Find them and murder them all."
Even considering that their MO is more along the lines of picking out the ones they can find and making a gruesome spectacle to scare the rest it still seems unrealistic, although so do a lot of things happening with drugs cartels these days to be fair.
This is not exact, unfortunately, because it depends also on some other factors. If the drug lords decide that they want to impose the fact that they don't accept opposition, they are actually going to do exactly that. They've done it already for several bloggers, it would make little difference if they decided to do it for the little indipendent dealers.
Keep in mind that in order to take out a few hundred independent dealears, they only need to torture and kill a few, and have the word spread.
http://techland.time.com/2011/11/10/fourth-blogger-reportedl...
source: http://www.nydailynews.com/news/world/member-anonymous-relea...
First, drug cartels have very easily control of the IT infrastructures, and second, they now employ hackers exactly to keep the internet information under control.
They've killed several bloggers already, and you can be sure they thought they were anonymous.
These aren't all of equivalent difficulty...
Apparently not hard enough. It is being done in Europe already.
http://news.softpedia.com/news/Six-More-Silk-Road-Drug-Deale...