A request from chevy-runs-deep.

"Tempest Shadow attacked Equestria and enslaved a bunch of ponies. She probably should get arrested for her crime."

Tempest, I think, happened to be in the wrong place at the wrong time. She never truly wished to harm others, she just felt that she needed her horn to be whole again due to her childhood experiences. As such, I think she would understand the moral and ethical importance of righting her wrongs and paying for her crimes. In this scenario, I think that she would not put up a fight towards being placed in prison, and rather embrace it as her just fate. Twilight would be saddened to have to send her new friend away, but I think she would see the importance as well.