[mcpherrinm]

At least in Canada, you're only allowed to have headphones on if they're earbuds (easy to quickly remove) and connected to the in-flight sound system (so you still hear announcements). I haven't paid attention to the onboard safety dance in ages, so I don't recall what it is elsewhere.

[alexeisadeski3]

Justification being that earbuds don't get in the way as much as headphones.

There is literally no end to the inanity of bureaucracy.

[MichaelGG]

My in-ear monitors are much more difficult to remove (not to mention get in) than headphones.