The mere act of a batter running to 1st on a dropped third strike is not in an of itself interference. A good mechanic for the plate umpire to use is to loudly call out, "The batter is out! The batter is out!" If the catcher still throws down to 1st then you just have a RDC* and you simply let the play develop. Just be careful that you don't use this mechanic with two outs.
*RDC - Really Dumb Catcher
|