Active ear protection become passive when the batteries fail. The active part is that they have microphones on the outside so that you can hear normally with them on. I do agree though that noice cancelling headphones should not be used as hearing protection.

I want this picture on a sticker so I can put it on every Tesla I see.

Iain M. Banks - Surface Detail has a really fucked up version of that concept in it.

This is Chappie, he is a norrbottenspets who thinks he is meerkat.