Writing for Kabitzin, Zyl reads signs:

The Shibuya outing has pushed me towards the interpretation that Kirino has brother complex (brocon) – wanting him to buy her that gauche heart-shaped ring and then making him take her to a love hotel (where nothing much happened) makes it extremely difficult to see her as not having brocon. There were other signs too – I might be reading too much into it but I thought Kirino looked downcast when Kyousuke refused, asked why he had to buy the ring and she said it was something that a girl would like her loved one to do for her, before hastily covering it up with the hypothetical and story research angle. In contrast, she was really happy with the heart-shaped earrings that he did eventually buy her and put them on as soon as she could. [...]

Well, daa. Rumours about the incest end were swirling for some time now.