In Lemony Snicket's "A Series of Unfortunate Events", the wealthy young villain Carmelita Spats insults the Baudelaire orphans by calling them cakesniffers. Presumably the insult is an antonym of "cake eaters", an insult reserved for rich, spoiled children (suggesting that they have their cake and eat it too). In calling the Baudelaires cakesniffers, the rich, spoiled Carmelita suggests that the (temporarily) destitute Baudelaires think longingly of her superior social position and wealth.
An insult heard in A Series Of Unfortunate Events. Everyone is trying to guess what it means, believing that it has something to do with cake, but I wanted to suggest that it might simply have been Lemony Snicket's way of censoring out the word "cocksucker" in his books.