I don't think it would be too broad at all, however:
Legality is always an issue on SE, they even closed the proposal - giving answering questions about legality can be construed as legal advice, which has legal standing of itself. Not to mention that it would depend greatly on location (complicated further since you are talking about more than one location - you might be in one country, your adversary in another - who has jurisdiction?)
hus, unless it's very generic and high-level, a question about legality would be problematic, and thus closed (if it's just about legality).
As for ethics, this can be very subjective, which doesn't really lead to good answers. There is a subset of ethics that can be answered cleanly, though, it would still be tricky to focus that. (E.g. CISSP's Code of Ethics, or any other defined code.)
I think there is some wiggle-room on the above, but it is not much.
For example, you could ask what laws or regulations would apply, depending on specific location. Or you could ask about the expected consequences.