Sustaining her transformation any longer would be a waste of energy and it would serve no real purpose.
The only way that it would be useful would be if she was close to the person she was following.
She was maintaining a distance while keeping her hood up so it was more difficult to tell if it was her that was pursuing him.
Her hair was her most defining trait and that was hidden so it would be difficult to identify her while the distance between them made it far more difficult to see anything else in detail.
She kept a distance and tried her best to remain out of their range of vision as she pursued him which meant that there was less chance of her getting caught following behind.
He eventually began to wander into a more busy area filled with a lot more activity.
Far more people were gathered all around causing it to become much easier for her to blend in with her surroundings.
