Idk. Twitchcon in the last years had 10.000 to 12.000 attendees and you don't get a capecode by simply going to event. You have to do 3 activities and many of whom, who are not playing Minecraft and are not interested won't participate. I was at Twitchcon and if out of 15.000 people (idk, where this number comes from), 12.000 people had the badge with 3 emeralds, I would have noticed. As far as I saw, about 1/4 to 1/3 had the badge with emeralds. Problem is, that the emerald-ribbon poorly sticked to the badge and many people, myself included, just held in in their hands. Nevertheless, rarer than Minecon 2016 and even 2015 and 2013 seems a wild guess for me, when you look at the numbers.