We aren't good at weighing long-term consequences, especially when we're young (as in the model's case) or in financial need (IDK if that was a factor here; it wouldn't surprise me).
Contracts between parties of such unequal bargaining power can't be ethically valid IMO, whatever legally validity they may claim.
Likewise, 20y+ contracts involving individuals aren't wise. (Fine for organizations like businesses and governments though.)