<I>A yeshiva bochur who is 17 when walking past a 16 year old girl on the sidewalk from a local bais yaakov on shabbos will say “gut shabbos” as a reflex.</I>
Is that true where you come from? I wasn’t 17 too long ago, and iirc, greeting a girl your age was certainly not a reflex! Have the standards changed that fast?
It’s never a full-on conversation. It’s just those words “gut Shabbos”. People do not even realize it. Not everyone is 100% perfect about doing it or not doing it every time- maybe reflex was slightly dramatic, but yeah, I have been greeted by Yeshiva Bochurim before like this. The standards though may depend on where you are living though. I tend to travel a lot.