Hermione felt confident that if her presence was noticed in Cardiff, no one would say anything unless she started making trouble. Her defection had been a well-kept secret. Only those with direct access to the Dark Lord via his Inner Circle even knew that she had run. It would have been a massive blow to morale and to the illusion that Lord Voldemort's favorite pet was still in line with the regime if word of her escape got out. No one would want the country to know that she wasn't still being a dutiful puppet.