Well... look at who it is. Riku knows his best friend had a thing for Kairi, but romance... when it came to the boy who was born and raised on Destiny Islands, it seemed like he was still wrapping his head around the concept of romantic love. There's so much that's different between the Sora he knew and the Sora he's run into here that... What did Riku know?

But yeah, he's pretty sure Sora would've found nothing wrong at all about spending the night in a girl's room unsupervised. Not that Riku was much fares better; he still feels like a creep if he sleeps in the same bed as another guy, even if it was to save his life when he nearly froze in a blizzard.

"Oh," Riku says, when she mentions how they built pillow forts together, "What you're saying is, you wanna do something fun together."