Very real indeed.

Some of these problems arise simply because the translation software doesn't have an ontology and therefore doesn't recognize category mistakes (like vodka not being the right kind of thing to be willing). The other sort of problem is a result of its failure to reason about probable utterances. This would require an even huger amount of knowledge. In practice, this is the issue: it's just too much data to handcode. But it's not a problem in principle, I would think.

The "cure cancer" -> "kill everyone" example is perfectly silly, by the way. In order to get that, you have to reinterpret "cure" in a rather non-trivial way, which actually requires malicious intent.