That's really strange when the game isn't on the 3DS.
Now some kind of surprise Splatoon game for 3DS? That'd be an interesting E3 announcement.
Nah, it is just part of the Splatoon Promotion Craze. ^^ Seriously, it has promotion literally everywhere. Really happy about that.
Splatoon on 3DS, though... can't deny I'd be interested.
Promotion everywhere can only be good [plus the 3DS install base is pretty nice].
Also they'll likely be more Smash Bros 4-like games [one for console, one for portable] with the NX platform, so may as well start synergising the PR across systems now [especially if the NX Console has Themes and Cases / Skins, like it should, too].