I know this is a bit late, but still looking into getting this up and running.
I'm a tournament director for the DFW Pinball League (one of the largest leagues in the world) as well as one of the tournament officials for the Texas Pinball Festival. In our tournaments; Extra Balls should be turned off in the ROM setting on games that it's able to be. With recent rule changes with the IFPA Extra Balls, if enabled, can be played as long as a one of the next balls is plunged. For an online tournament; I haven't figured out any way to enforce this other than "good faith".