The hypothetical is that your sister would fuck you, and this would only occur in a dynamic that is NOT normal. Hence you bringing up the dynamic with a sister is not a valid argument as this is not what's being asked (if you understand the implications) as it would not occur in said conditions. Now you might be thinking, "but you mentioned the dynamic between you and your caregiver?
" Yes, I did. And this is because I was discussing the relationship you had with the OTHER caregiver which would influence your decision with the altered dynamic with the mother. Also people who do have sisters answer would be influenced as a hot sister would make them picture a different girl/version and dissociate that from their actual sister so the responses are likely skewed.