Yes, the first situation is definitely an extreme case, but I would blame the person who failed to specify what the boundaries are, assuming they also failed to do so during the act, allowed things to proceed and complained after. I mean, nobody's expected to be able to respect rules they're unaware of, and while in case of the law lack of knowledge doesn't absolve one of responsibility, when it comes to such interpersonal situations, unless what is demanded is made perfectly clear, you can't be responsible for failing to do it. People aren't usually telepaths...
(On the other hand, if the one who had mentioned boundaries clearly tried to stop things during the act once they were crossed and the other pushed through regardless, the blame lies on said other instead, obviously.)

In the second, on the other hand, nope. A robbery in that case is solely on the robber, and the one being robbed has the right to defend themselves and their possessions too. No different from the skimpy clothing invites rape "argument". We need to strive for a society where such things don't happen, and while we don't have it at least make it clear that we won't accept the current state of things, not blame the victims for the "stupidity" of possibly exposing themselves to the malicious intent of others.

... Still not the topic of this thread though. Then again, there is another thread now started basically for the topic of this one...