Two points:
1. In reference to the rain scene it seems everyone's concern was for good reason. According to imdb Hayden Christensen badly sprained his ankle during the scene, causing him to miss a week of shooting.
2. The reason for Emma Robertson leaving was speculated. I felt the movie attempted to explain it as her "leaving a place that never changes and seeing the world".
This sentiment is fine, except for the fact that she was clearly born in Toronto. As someone living in a city nearby, I assure you it is no small town. Toronto is one of the most diverse and most populated cities in Canada. All she needed to do was move a couple blocks, not go across an ocean.