What Were They Thinking?!

Last evening attending OSLO at the Lincoln Center.  Seated next to me is an older couple, well-dressed, nice looking, cultured.  Until.  They pulled out little brush-teeth-cleaning-sticks and used them, somewhat discretely, before the start of the play.  When they left for intermission and at the end of the play, the used sticks lay on the carpet in front of their chairs.  Words fail me!