How do they know if the noise cancelling is on or not anyway? I have Bose noise cancelling headphones I love, and if I want to sleep right away or have noisy kidsnearme near me or am in Y with 2 seatmates that are talkative, I like to keep the headphones on with the noise cancelling off until we reach 10,000 feet to help block the noise out.

A couple times I have had FA's ask me if they were turned off. Only time I was told to remove them was a couple months ago sitting in an exit row. The FA said I couldn't have headphones on so I could hear announcments in case of an emergency (yet they weren't concerned about an emergency over 10K feet????). I have had them on other times in an exit row with no problem.