This is a good lesson for all of us. Something is misunderstood, and a letter is written to management, put into the employee's file and the employee is reprimanded. Pretty harsh action for a friendly comment from a FA. Kudos to the OP for getting this aired out with a reasonable explanation after all.

And, I can sense their frustration with the Bose headphones. Is there a LED or anything visible to let them know they are powered or not?