In the future, it'll help us greatly, if you find the original source to the images as after all, twitter isn't the best source.
[this helps to find other information in the site, could be location, type of distro etc]
For now, using the keywords in the images, I've found these links: http://m.ruliweb.com/news/board/1001/read/2124315 http://www.nintendo.co.kr/3DS/software/pkmsun_moon/pop_event.html
http://m.ruliweb.com/news/board/1001/read/2124306
https://story.kakao.com/ch/nintendokorea/
Anyhow, it's a local wireless event!