[qohen]

This is absolutely not a solution if you have tinnitus or a hearing damage or both.

Arguendo, one could wear headphones without them being plugged in, strictly for signalling purposes, if it were necessary.

[Illotus]

So how does that work agains overhearing conversations etc.?

[dx034]

Some studio headphones have excellent passive noise cancelling. They're designed to avoid sound leaking through so they basically shut out most noises even if they're plugged off. Look at DT 770 as an example.

Which also means you can use them on a very low level so that they don't cause hearing problems if used for long time.