Susan Collins and Angus King both refused to take questions from the media after a public appearance Monday at New Balance’s central Maine factory, an unusual development for two often-accessible elected officials. A spokesperson for King, an independent who caucuses and often votes with Democrats, said New Balance organized the event and did not include a press briefing. Blake Kernen, a spokesperson for Collins’ office, later said the senator had another visit she had to attend at a local school. A citizens’ group in Portland held an “empty chair” town hall this spring after Collins declined an invitation to speak at the event. “The people of Maine deserve to have a senator who listens to their concerns and takes their questions,” Platner said in a statement Monday.