(Someone might ask, "Why provide an interactive question and a link; why not just quietly redirect?" But that defeats the purpose of being caseful and makes it difficult or impossible to create a second entry with the other case. If you're going to redirect in this case, you might as well turn on $wgCapitalLinks and be done with it.)
I cannot follow this line of reasoning. The purpose of "being caseful", as you call it, is to have (1) correct article titles, and (2) the potential capability of having separate entries differing only in their capitalisation. Neither of two have anything to do with redirects.
I would favour an approach where, if the user visits a title that doesn't exist but the same title with different capitalisation does exist, the software pretends there was a redirect, and displays the "redirected from" message that allows you to click back to the original title in case you actually need to create a separate article. I would actually favour the same approach on Wikipedia too.
Timwi