Summary (feel free to respond after reading this if you don't want to read the whole text wall): If I, a US citizen, were to propose to and marry my long-time, long-distance girlfriend (non-US citizen, B2 visa holder) on a future visit she makes to the US, and then she were to subsequently apply to adjust status to a green card on the same trip, would this open either of us up to allegations of wrongdoing/visa fraud? The key point here is that the whole plan would be something I spring on her only AFTER she arrives into the country, which she wouldn't have previous knowledge of.
--------
I'm a US national, and my foreign (non-US citizen, B2 visa holder) girlfriend and I have been in a long distance (international) relationship for a number of years. We've talked of marriage, and both understand the fact that it's the only way we can close the distance be together permanently. We've also talked of the idea of the US being more likely the place we'd settle, between my country and hers. She'll also be graduating from university in the near future.
I intend to propose to her soon, and I have no doubt she'll say yes. However, I understand that the typical route for someone currently outside the country who is married to--or intends to marry--a US citizen, is a K1 or CR1 visa, and that those are taking forever (+18 months?) to process right now. As an aside, we have a rock solid story and plenty of documentation, and friends and family from both sides who can attest to our longstanding relationship, so maybe that would expedite the process? In any event, I understand that a likely faster route would be for her to arrive on some other kind of visa (either B2, which she has, or J1 or F1, which she is considering applying for in order to work temporarily/study for a grad degree here after she graduates undergrad), and then for us to get married and for her to file for an AOS to a green card.
I understand its illegal/visa fraud for her to arrive on one of the non-immigrant visa types I mentioned, with the intent to try to adjust status on the same trip and get a green card. However, what if that idea comes from me, the US citizen, and it's a plan I spring on her/propose to her only after she arrives? Would either of us open ourselves up to allegations of wrongdoing/visa fraud in that case?