I wasn't at the Nationals this year, so I don't know the Stage in question. But, the current IDPA rule book does state that there is no 180 degree rule in IDPA and that 'muzzle safe' points shall be used instead.

If there was no 'muzzle safe' marker to the side the shooter got DQed on, and there was one to the other side, and after shooters complained about the DQ they then put up a 'muzzle safe' marker on that side... why did they DQ this shooter? It sounds rather arbitrary to me.

But... that wouldn't be the first time with IDPA rules Laugh

ISTTTWFT Smile 

Chris Christian A23489   former SO 
Arguing with a fool is like rolling around in the mud with a pig. You both get filthy dirty, but the pig enjoys it.