[gilga]

Adding cups over a user’s ears provides protection not
unlike eye covers for cybereyes. This acts as Armor 3,
though only to protect the ears.

I must say that altough this paragraph seems like it is all rules and no fluff... as far as I know individual organs do not have their own armor, and you can't shot at the cyberears and ignore the armor of a person. (can you?!)  that said... what does it means to have armored ears. 

[Reaver]

My guess?

Sonic attacks, or other just uses.
For example flashbangs. They make a loud noise and a bright light.

IF circumstances allowed that the light didn't affect you, conceivably, these would provide a resist modifier.

At least that is my take on it (won't have the book until DTF comes out)

[ScytheKnight]

Would also protect from Called Shot: Ear from Run & Gun?

[Kincaid]

Would also protect from Called Shot: Ear from Run & Gun?

This is what I thought when I read it.  Called Shot: Shin is actually a decent one--maybe those snake socks will come in handy after all.