The amount of will necessary to close a window is itself trivial, if will can indeed be considered a resource to be spent.
I've had drops of 5 or 6 karma at a time as someone goes through and downvotes all my comments in a particular thread, but I think that's the price we have to pay; by and large, the karma system here seems to work very well, and provides a very useful method of gauging posts.
Do you have a link to some well-written material on the subject? You've piqued my curiosity.