That Twitter status update URL problem

I just thought i'd cursorily document a bizarre quirk with Twitter's status update system, that we at Torchbox seem to experience every n months or so, when a new client asks us to integrate. It's simply demonstrated, thus...

Visit this URL:
http://twitter.com/?status=I'm testing how well this gets encoded

Then visit this URL:
http://www.twitter.com/?status=I'm testing how well this gets encoded

For some unknown reason, calling twitter with the ?status query string, at the WWW-version of the domain causes the query string to become unexpectedly URL-encoded. Visiting the naked domain does not. Just don't use the WWW-version and you'll be laughing. Mainly at Twitter, for this seemingly avoidable stupidity.