Kjos, yes, I understand those who bought the game from TellTale's store get the extra episode for free. Although I believe those who purchased the disk version should be allowed to do so as well, I'm still okay with paying for it . . . if I were given that option.
I don't see why they would cheat those who purchased the disk version out of playing the episode. Unless there is an option I'm not seeing.
EDIT: Well, I'm not happy about this. I was looking on TellTale's forums and found this info here - http://www.telltalegames.com/forums/showthread.php?t=47236.
And I assume by proof of purchase, they mean some sort of receipt, which is long gone by now. I'm not about to re-purchase the game just for one extra episode, so it looks like I'll just be watching someone's playthrough on YouTube. Not happy at all.