He laughs outright and briefly considers capturing that hand - but, no, he doesn't want to do anything to set off her guards. At best, it could lead to an end to the conversation; at worst, it could lead to them clubbing him to death.

"I suppose I'd have to search for evidence one way or another." He strokes at his goatee, and then says slyly, "Is there an enchanted mortar and pestle concealed on your person, perhaps? Hm. Where could you be hiding it? Turn out your pockets, let's see if there's one in there."