Since we're talking about martial arts, a reasonable expectation of a situation is one in which one party wants everything - your money, for example. I wonder if a selfless act would be effective in this situation?
No, probably not. Unless maybe they would be likely to escalate the conflict much further and by giving them the money you avoid escalation and get away with no money but unharmed -- but clearly that would not be a best-case ending! Not really a success per se, more like harm mitigation. This is a relatively predatory kind of conflict.
However there are many other kinds of physical conflicts, e.g., involving loss of temper, loss of 'face', perceived threat, and so on. Hotter, more irrational kinds of conflicts, I guess you could say, rather than cold ones. I think there are definitely some
conflicts, even very dangerous physical ones, that can sometimes be resolved by better communication such that each party can get what they want.