I've seen the response change a lot in the (almost 20!) years I've worked in IT. It used to basically just run its course, and would basically ***** up everyone's email for half a day, or how ever long it took for all the dummies to respond (sometimes more than once.)
These days I think the email Admins must be able to quickly disable an email list when something like this pops up, and usually they're shut down before they really start.