The first thing I saw when I went to the artist's Pixiv page was an image of a drooling Dia taking pictures of Ruby. I was about to question the presence of a pairing tag for fraternal hugs, but it's clear the artist actually ships them(his current profile image is even one of Dia drooling over a Ruby doll). Now to wait and see if they put out a full-length doujinshi or if it remains confined to a couple of loose images.
@Nezchan, with the moral victory: Fair point. And being able to catch an adorable fortuneteller off-guard with a kiss is probably worth it as well. ^_^