QUESTION:
Is there any possible reason or situation that could arise in which you
would direct the rover to drive back up onto the Pathfinder's pedal?

ANSWER from Pieter Kallemeyn on July 28, 1997:
No, there is no reason to drive back onto the petal.  Doing so would shade
the solar array on that petal, reducing our available power for the lander. 
Besides, if you were a rover, wouldn't you rather be out running around and
playing on the surface of Mars?