In the pilot episode for 'Harry's Law', the theme song for 'The Jeffersons' could be heard as attorney Adam Branch made his way through a seedy Cincinnati neighborhood to the shoe store where Harriet Korn was setting up her fledgling law firm.
This isn't a Zonk because it wasn't being heard by the people in that scene. Like screen credits, it was only there for the benefit of those in the Trueniverse who O'Bserve the fictional universe of the Toob.
If anybody could hear it from within Toobworld, they would have to be tele-cognizants, like David Addison of 'Moonlighting' - those people who know they're living in a TV Universe. (Lt. 'Columbo' once displayed tele-cognizance in the big revelation scene of "Last Salute To The Commodore".)
There could have been a pozz'ble Zonk when Harriet's secretary Jenna mentioned 'Law & Order'. But that's such a generic title, it could have been any kind of legal show, including a reality show like 'Cops'.
And that's an important Zonk to be dismissed, because I'd like to think that Adam Branch is the nephew of Arthur Branch, the former D.A. of New York City, as seen in 'Law & Order'.