I’m in my late 30’s, and I was a high school educator for about a decade. Teenagers have become quite comfortable holding an entire conversation while wearing earbuds. As an ancient and outdated old person, my initial gut reaction was that it was… a bit rude(?); however, these teenagers just internalized that audio pass-through was a thing, and wearing earbuds didn’t indicate a lack of attention to the conversant. My point being, we may not be comfortable having a conversation indoors with sunglasses on today - but that could change in a flash and only ‘old people’ would even notice.