Hello Commanders!
I just thought I'd drop my own two cents in here.
The concept of Multi-crew, at its core, is about cooperation, and trust. If folk are going to troll each other, there's a limit to how much protection we can (or should) put in place.
One of gunner's abilities is to be able to fire countermeasures. Gunner can be effective at this, poor at this, or deliberately bad. Anyone who would want to go down the last track is, in my opinion, someone I would not want to Multi-crew with, or wing with.
To some degree, folk have to take responsibility for their own actions. There's no mechanical upside to this unpleasant behaviour, so I see this as different from say, crime, because the game actively encourages criminal behaviour; when folk complain that the justice system is not fair enough, we say "OK", how can we address the balance and make it fairer.
Firing shield cells repeatedly for no good reason is just an unpleasant thing to do. And I'm fairly certain it is more likely to be detrimental to the community than helpful.
It should be an option for the ship owner to tag systems in the Fire Group section for use by crew then.
So instead of fire group 1 and 2, add a third option that's M to allow us to whitelist modules for use by joining crew members or something.
I agree that it should be on the pilot to protect themselves from trolling but right now you are essentially saying that if they want to do that they should just not use multicrew.