I don't want to disagree with your general statement, because it's correct, but I would like to point out that wearing noise cancelling headphones is not a good signal of ``in the flow, pls don’t interrupt.'' The only thing it's a good signal of is ``I'm listening to something.''
Some people wear headphones simply because they want to listen to music or a podcast while they send/check email. Some people only put them on when they're in a meeting. And yes, some people wear them because they want to be left alone.
There are as many reasons to wear noise cancelling headphones as there are people wearing noise cancelling headphones, and assuming that everyone around you should know what it means to you is as insane as walking up to someone wearing noise cancelling headphones and asking for an update.
Some people wear headphones simply because they want to listen to music or a podcast while they send/check email. Some people only put them on when they're in a meeting. And yes, some people wear them because they want to be left alone.
There are as many reasons to wear noise cancelling headphones as there are people wearing noise cancelling headphones, and assuming that everyone around you should know what it means to you is as insane as walking up to someone wearing noise cancelling headphones and asking for an update.