The Immigration people, are very fickle. It is dicey... as to whether she will be let back in.
I have friends, who do not leave the USA, because of this. They are from Europe.
My husband, is from Europe. HIS papers were fine, he was a bona fide legal Resident alien, ie: green card, and when he went to update his records, they tried to deport him. For no reason. Just out of being jerks. They even insulted me, for being with a "foreigner" etc.
They even put him in a cell at Immigration. I got an Attorney... it took time to get him out. It was horrendous.
they had NO basis to do what they did. We almost sued.
My Husband is now a US Citizen. But that horrible experience he had prior, was just a complete night mare.
I would be very wary... of leaving the country and coming back. I have seen others, who are prominent law abiding citizens from all socio-economic levels, who were not let back in... again, for groundless reasons. There was nothing wrong with their status or paper work.
Again, do not take it for granted.
It is not a rumor. These things DO happen. And there is no way to predict it. It is and can be a VERY complicated capricious matter. The 'rules" do not always apply.
Take care,
Susan