That seems like a likely result if its obvious that the student visa is just a back dooring the immigration process. I was more thinking that she'd go to the US and then when her program was done then get married.I would take legal advice before trying that. I know someone who was in US on a student or work visa (can't remember which), married a US citizen and then applied for a change of status based on that. She was deported for 10 years!
I know plenty of people who met their spouses in the while in university abroad in the US. So it can't be an automatic rejection.
Or depending on what she does, she could apply for a H1 B and go to the US and marry there after a few years and then change.
Since Argentine weddings aren't actually legal until you go to the registro civil (i think), the OP could even 'get married' here and still be single legally.