Cat on the hat

I bid on this cel because I liked Kaoru's pose and expression, but when it arrived I discovered there is a cat design on her hat. Now I'm completely intrigued. I can't imagine that the animators wanted to draw this design on hundreds of cels. Was this just slipped in as a kind of subliminal cat motif?

I lightened the hat somewhat in Photoshop so you could see the design better, but to see it really clearly take a look at the sketch.
 

Added: 8/25/02 From: eBay penshin
 
Cat on the hat