Connecticut holds its presidential primary on April 24, and Pennsylvania holds its primary for president and all other partisan office on the same day. The various minor parties that are petitioning in those states will make special efforts to have lots of petitioners stationed near polling places on April 24. Petitioning outside polling places is generally very fruitful. Virtually everyone on the scene is a registered voter, and frequently people must wait in line and thus are more likely to be receptive. Many states do not permit petitioning within 100 feet of the entrance to a polling place, but this restriction is generally not so severe as to interfere with all petitioning.
Connecticut and Pennsylvania election laws permit stand-in presidential candidates on petitions.