My comment that fraternization is an odd term referred to the fact that, literally, fraternization means “treating someone like a brother”. I know the term has been used in the military for decades, and I know what it means. My comment was that most fraternization relationships these days are not fraternal in the literal sense of brotherly.
I don’t think SS prohibits fraternization between two trainers in a given barn, or two adult working students, if there is no power imbalance, although some universities or businesses would prohibit relationships between employees even without a power imbalance.
If a significant power imbalance exists, whatever ostensible consent has been given is tainted by the power imbalance. No, it’s not as bad as forcible rape or sex with a minor, but I agree with SS putting the burden on the party with more power to refrain from indulging in a relationship in which the consent of the less powerful person complicated by the power imbalance.