Illegal hobbies might be.

*It's still light, conversational, as he gently touches the Detector to each bottle in turn--the result is utterly unambiguous, and with a wave of his wand the five of them disappear. As he turns to Malfoy he might as well be reading from an Auror script--but there's a definite twinkle in his eyes.*

Sorry, we'll have to confiscate these for testing. Is there anything else I should know about?