The thing is, is it really that risky?
I don't know if you have a sister, but surely you had a mother who gave birth to you. If she hugged your arm, held your hand, or kissed your cheek, would you somehow guess that some cliche fuckboy roofie'd her, blackmailed her for sex for a month or two, only for her to break free with the power of incestous love?
Most likely, not really.
Not only is the Kirito in this Fujinoverse kind of an autistic cuck who would never truly guess what Suguha intends to do, even regular Kirito wouldn't guess that his sort-of sister wants his (sometimes) microdick because she is a bit more affectionate.
Well, at the end of the day, I am just complaining because the best girl didn't get quality time in the lewd spotlight in a random parody game. So there is no need to really go on and on with this topic.