I think one would have to weigh the pros and cons of this kind of research. In particular, the main cons (IMO) are:

* users are misled about facts * trust is lost in Wikipedia * other users/organizations use this as a blueprint to insert false information

Harm 3 seems to be the most serious, but I suspect it has happened/will happen irrespective of this research. As opposed to the water reservoir example, these harms seem quite small by contrast. I would have liked to see a section discussing this in the blog post, but perhaps that's included in the original paper.