Actively seeking out the wizard who sought to ruin her life was a drastic risk that Hermione knew she had to take. Sitting around just waiting for the next terrible event to happen was no way to live. Neither was being ignorant of what was to come. Clearly, Rodolphus had a plan for her and she wanted to know what it was. Maybe she would come to regret crossing over into enemy territory, but something told her that she would regret not going even more.