There's a thin line between can't and shouldn't, though, isn't there?

[While his gaze is still fixed on the seagull, which opens its wings to lift off and fly away with loud sqwaks, he shakes his head slowly.] Most animals? Maybe, but birds are a lot more sensitive, that with having some sort of internal magnetic compass. If whatever they are or are using is making some people uneasy, I'd be willing to bet it would at least make them quiet. [A tilt of his head, as if acknowledging Hux's caution.] Still, no reason for us to lower our guard.

[Covered by the mask, Hux may not see Mamoru's focus solely on him. Maybe he does sense it, though, having been surrounded by many people wearing them.] So. A higher chain of command?

Why do you think they haven't, then, if they're able?