Why Is Isabrie Considered An Immigrant Or Prisoner?

Isabrie stirred, the sound of hooves hitting the slick ground and gentle rocking motions of a wagon greeting her. Though the bite of rough rope bruising against her delicate skin were what had initially coaxed her into consciousness, it was quickly forgotten as she realized her status as prisoner of the imperial soldiers that surrounded and lead the wagon trail she found herself a part of. What she had done to invoke their wrath she did not know, but she knew the budding sense of dread she felt was not misplaced. Her fate was shared by three other men, nords, dressed as what she considered it a solider, a peasant, and a noble to look like. So far, it was the intro of a particularly cliché joke she mused as she glanced over her surroundings.
Walked right into that Imperial ambush, same as us, and that thief over there.” He stated, motioning his head to the man next to him. She kept her silence as she thought over his words. An imperial ambush at the boarder? The last thing she remembered was searching for the nearest village or hold after her only map of the province had been lost to skyrim’s harsh weather.
She had hoped that sticking to the roads would lead her safely to back to civilization, but the gods had other plans for her apparently.
"Damn you Stormcloaks”, The thief spat out bitterly, “Skyrim was fine until you came along. Empire was nice and lazy.”
She had heard rumors of the Stormcloaks and their revolt against the empire while she was still in High Rock, but she never thought that she would come across them in her travels. If the Imperials had mistaken her as a part of their foolish rebellion, then it was likely that this would not end well.
“If they hadn't been looking for you, I could've stolen that horse and been halfway to Hammerfell.” He accused as he turned to face the young Breton with a look of desperation. “You there... You and me, we shouldn't be here. It's these Stormcloaks the Empire wants." She avoided his