Perhaps the earliest example of this was Felix the Cat, used by early mechanical television stations in the late 1920s to claim their part of the broadcast band [1]. They placed a wooden model of Felix on a turntable, trained a 120 line "flying spot" camera on it, and left it on. I read a contemporary account of watching an early televised prize fight which mentioned this as well, but I can't for the life of me find it anymore.

[1]: http://framemaster.tripod.com/Electronictv.html