Most of the time when I talk about rule differences it is between varying levels of baseball. Turns out some baseball umpires also work softball. There are some rule differences there as well. Some of them are pretty goofy.
Take this play for example:
In baseball, this is a nothing play. The runner backs up the first base line and is eventually tagged. He would be out once he went beyond the plate.
In high school softball it is illegal to back up towards home plate. The ball is dead, the runner is out, and all runners return to their time of base pitch. That is a pretty harsh penalty.
The question of whether a runner can do this in baseball comes up every couple of months on umpire message boards. As this play shows, the answer is clearly yes.