Kylarnatia wrote:After all, with everyone and their mothers
My mother's a saint Kyl
In all seriousness, as others have stated there isn't really an accepted standard of international law in II. Many, if not most, of the various II-focused RPing regions out there don't really recognize the WA as being a thing in the RPing universe, so the closest you'll get would be regional/interregional agreements, or the standards of various alliances.
Keep in mind, though, that it should also be acceptable to the people you're RPing with. A fair number of people might not want to RP with you if your standard operating procedure is, say, ripping every prisoner's head off even though there's no explicit 'international law' against it. So if you're going to do something that may be outside the bounds of what is acceptable in RL warfare, at least make sure your partners are aware of it. If they're fine with it, by all means go ahead and use exploding bullets and the like.