I do remember he appeared briefly in the South Park episode, ImaginationLand. He didn't have a full-on speaking role, but he appeared alongside several other fictional villains (Ganondorf and Bowser among them, too).
It's just a coincidence. the episode was aired almost three years before Wario was even heard of.
We can place this in the same category as the ''Mona in Wario Land 4'' thing or some people claiming that Foreman Spike was an early version of Wario:
Unlikely, but still interesting.