I think I understand problemaddict's point about how the Jonestown referrence could kill the discussion with JWs. It's not that the Jonestown referrence isn't a fitting warning about what blind obedience can lead to. It's just that the typical JW is so indoctrinated that he won't think deeply enough to see the connection being made, but will only see on the surface that the Jonestown massacre is nothing like what currently exists among JWs and would just dismiss you as an apostate exaggerationist.
Regarding the point about not seeing JWs following through to drink the Kool Aid here are some facts to ponder on:
1. Most/many JWs believe that the organization is "Jehovah's Organization". Someone who has left the organization is described as someone who has "left Jehovah". Already, most/many regard the instructions and teachings coming from the organization as coming from Jehovah. Subconsciously they equate the organization with Jehovah.
2. JWs already devalue their present life. It is not uncommon to hear a JW, in arguing against the taking of a blood transfusion, make statements like: "should we disobey Jehovah to prolong our imperfect life in this old system of things?"
3. JWs are already willing to die - to essentially commit suicide - and are doing it in obedience to the organization! How so? What does a brainwashed JW do when his life depends on receiving a blood transfusion or treatment involving primary blood fractions and there are no effective alternatives? He refuses, essentially committing suicide! Brainwashed JWs, individually, are already drinking the "Kool Aid" by refusing lifesaving blood transfusions! And let's not forget about past JWs who drank the "kool Aid" by refusing organ transplants back when the organization taught against it.
Add to all of the above this new directive to be willing to obey the organization even if what it says does not seem sound or strategic from a human standpoint. In any future situation where JWs are told by their organization to drink the "kool aid", this latest directive will play on their minds. They will be thinking: "Yes it sounds strange, impractical, crazy, but I remember that November 2013 Watchower that said we must be ready to obey even if it doesn't seem prudent from a human standpoint. Am I going to trust in Jehovah or cave in to fear? I must be loyal to Jehovah even if it costs me my imperfect life in this dying old system. . . I must remember the closing words of Song 7: 'No longer as living for ourselves, For you we shall live or die'"
Sure, not every JW will drink the "Kool Aid" should the GB go all Jim Jones on them. But with roughly 8 million JWs what percentage do you think will obey? What percentage of JWs do you think are brainwashed enough to do it? If we conservatively say that 2% will obey that would amount to 160,000 deaths! That's roughly Jonestown x 160!!
But don't lose sight of the fact that it is already happening with the blood issue! I'm sure more JWs have died refusing blood over the years than the number of deaths at Jonestown.