"As they do to me as well, Miss Gaunt," he murmured simply, in regards to the Muggles. This was, of course, where it became tricky. Now that he knew for a fact she was staying with her son, it was only a matter of time before their paths would cross again. When that happened, he had to have made certain not to have given her any reason to doubt his own loyalty to the cause that her son and his Master held so dear.
Yet he also didn't want her to believe that he was a threat to her, as clearly she felt the Dark Lord to be. So he was careful about what he said, and how he said it. Exact wording was critical, as always.
A slow nod of his head and he responded in a noncommital tone, "If that's what you wish. I shall not stop you." He thought of adding he prefer she didn't, but stopped himself. Instead, after a brief pause, he stated, "However, given the dangerous condition of the streets in this city, I would be much relieved if you would allow me to at least ensure you arrive at your destination safely."