"It would not hurt to be aware of newcomers who know your face. I have been, on more than one occasion, hexed by wizards and witches from my birth world who recognized me and then... overreacted. Because I was their enemy. It hasn't happened in a very long time, and Security handled each situation promptly with no harm to myself or to them," he says, trying to reassure the younger man.

"When it first happened, it was dismaying. Quite a shock. It may never happen to you, and I certainly hope it doesn't. But I wanted you to know that, well. It could."