There is a certain extent where bad decision making should be allowed to be it's own punishment.
Since rape is the discussion that spawned this:
You make the decision to go out to a club. Most people go to the club to drink and meet people. Many go to the club to meet a partner for sex. Then, while at the club, you make the decision to drink. And drink, and drink, until you are very, very drunk. And then, while drunk, you make the decision to go home with someone and have sex with them. Realistically speaking, yes, the other person involved was probably a tremendous piece of shit taking advantage of a drunk person, but at the end of the day do you really have anyone to blame but yourself for every decision made that lead up to that?
You made the choice to go to the club (where you knew people would be looking for sexual partners) and you made the choice to get incredibly drunk. (where you knew your judgement would be impaired.) If you made decision A, and made decision B, whether or not you were mentally capable enough to make decision C, you put yourself into that position knowingly and willingly, and I would say at that point you lose the ability to rationally make the argument that you are blameless.
Context is important here, of course. If you choose to get out of bed, put on skimpy clothes and walk around a bad part of town and someone viciously assaults you, I think you do deserve a certain amount of scorn for being fucking stupid, but that does not mean your attacker should be punished less for your stupidity. I do not, however, think that you should go without being shamed for being a moron. The same applies to, say, the wall street investor who flashes a huge wad of cash in a sleazy bar and gets mugged. You were being really dumb, and you deserve to be made to feel like you were being really dumb, but that's something that should be wholly segregated from the actual crime - the guy who mugged you is still a criminal who used the threat of violence (or actual violence) to steal from you.
The primary distinction between these cases is that in one situation you chose every step of the way to be a victim, and in the other situation you simply chose to put yourself in a very bad position. I still think in the secondary situation, you are certainly at fault for your own fate, and I think you deserve to be reminded of this. But I do not think that should come into play in a court of law.
In a less extreme example of choosing to be a victim, if you are choosing to play a shell game on the street and you get cheated, you are pretty much entirely to blame for choosing to play a shady game with a shady guy who you knew might try to rip you off.
