Steve, you are so right. There are different ways to leave. She basically resigned. While it is possible for her to come back, I find it quite unlikely.
Also, #9 in a class doesn't necessarily mean "In good standing". Remember how many 4.0gpa types never even received an appointment. There's a lot more to an individual that their grades or class standing because of the addition of military studies and physical fitness along with their GPA. If she was allowed back in, a good portion would probably be politically motivated.
LITS: You are also quite correct. Even if they rescinded the policy tomorrow, the military would request, and be granted, a phase in period. Especially considering they have not finished the survey and the pulse of the military members. There are NUMEROUS logistical requirements that would need to be addressed prior to allowing gays to openly serve. I know there are some here that will say B.S. and that they are serving today without the additional logistics in place, but it is still an issue. DADT in it's very nature implores a certain amount of ignorance among all individuals involved. Once that ignorance is removed, and all individuals become aware of everything, personal conflicts and issues WILL ARISE. These will have to be addressed and anticipated to an extent. So I would guess that from the time of rescinding the policy, to a complete and open gay military, would require a phase in of approximately 2-3 years.