Interesting technique. Perhaps this is an opportunity to specifically allow a colophon/about page (rather then allowing a redirect). If a user browses to the theme's directory then it might be nice to have some info about the theme and it's designer, IF it could be done without effecting the site's operation. It'd have to be considered whether it could be abused (links) or effect the site it's on (content index by Google, etc.) and if there's any realistic work-arounds (no-index, no-robot settings, no-follows, no links at all, links only to <a href="http://wordpress.org">wordpress.org</a> theme page, &c.). <br>
<br>Perhaps a best practice recommended way of constructing the page, or an autogenerated page using data from the repo meta?<br><br>It'd give a legitimate venue for designers who otherwise would like to add credits somehow. (As long as they don't claim that it can't be removed)<br>