"Oh, his headphones are on. He's working."
"Oh, I see airpods. Better let her be."
Yes... but also no! Headphones are the standard "Don't bug me I'm working" tool (for now), but they're imperfect. Sometimes we snap them on to listen to our favorite band, or watch a Youtube tutorial, or maybe to use the noise cancelling to block out the jackhammering outside.
Here's how FocusFlag fits in with headphone usage: flag up, flag down, and nothing at all.