There's a few possibilities:
1) Sage and some of the other HOTs know, but they don't gain anything from it. Normal individuals don't have a "responsibility to rat", so they would not be charged with anything.
2) The HOT sorority benefits financially (for example paid tuition, the upkeep of the house) from the prostitution money, but Sage and the others don't know from where Quinn's money comes from. Those who don't know cannot be charged, including Sage.
3) Sage knows and gains financially from it, but nobody else does. Quinn and Sage will be charged.
4) Sage and the HOTs know that prostitution is the main source of income for the whole sorority. Then everybody in charge of anything and/or benefiting will be charged.
5) Prostitution is only one source of income, we've seen that drug trafficking might be another. Illegal gambling might another. Everyone in the sorority know and benefit from it. Therefore I think the whole lot can be seen as a criminal organisation and can be charged according to
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, and the FBI will imprison everyone.
6) Professor Burke knows, but doesn't inform the authorities, though
he is by law responsible
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Choose your favourite. I doubt DPC has thought this much about it as I did. Or maybe he has.
In any case if this all falls apart, Riona, Camila and Sarah won't be criminally responsible, even if they did it voluntarily, they are considered victims. Unless they did some crimes themselves of course.
And, if you playing as the MC bought "food", you will get charged as well as an accomplice. If the FBI is gonna get involved, you better start a new game and reject the food offer from Quinn.