I'm not saying they did it alone, or quickly, but at some point you become good enough at reading WoW logs that you realize you can build programs that could interpret them for you and do a lot of the difficult work of finding out what happened to items the player started with (and which items were actually gained during the hack, as when a character is used for farming until locked out) and so you write a simple script. You show your manager, it gets approved, and now all top tier support staff is able to be more efficient at the job that takes them the most time. Iterate through this process with different GMs writing different tools, some help from the WoW dev team and other teams so that different log files are created which are easier to interpret. I can't give specific inside information, but I'll say it used to take hours to restore a hacked account but last week my wife's account was somehow compromised (we think when we used an Internet cafe to play, or possibly due to a shared password—either way, it took a former account investigator seeing his wife hacked before finally adding Phone Secure to protect himself) and she had an in-game mail with her lost stuff within an hour of reporting the hack.
So yes, the tool building was voluntary (eventually sanctioned and encouraged, even of it was unofficial at first) and that directly led to an increase in productivity (supply) which has come to a head with demand decreasing simultaneously (referring both to drops in subscription levels and, more importantly, even the long tail of WoW players being incentivized and easily able to add forms of multi-factor authentication to protect their accounts and prevent the compromises in the first place). It would be cynical to see any of these advancements (except the lower subscription numbers, of course) as bad things, but also naïve to ignore that they're a large reason why the department finds themselves in a position where they're starving for work (mostly a guess on my part, based on response times to in-game support requests, coupled with interpretations of the layoff and Blizzard's official statement about it, as well as knowledge of who I knew that was affected and who I knew that wasn't).