This should come with a lot of preloaded/example messages which we've seen already. "How do you people make a living?" or "My children will go hungry tonight" could be sent right back at them.
This would add to immersion, in realizing many of the messages you receive from pirates, etc, are preloaded. While they attack, they're concentrating on taking you out, while their comms system is sending you preloaded messages. Hmm, so maybe have a few directly linked to hotkeys, but also, if you get into a fight, your comms system could also send autoreplies?