Exactly. These links are not meant to be posted online or meant to last forever. The main use-case is to share them aloud with other people in the room (or write them on a whiteboard at a hackathon). I mention quite clearly that the links are temporary, so people that use them otherwise are missing the point I think.
So ideally you want people entering links directly into the url bar instead of creating a page link somewhere. You could detect that reasonably well with the Referer header, and perhaps provide a warning against that behavior? food for thought
It might be terrible from a usability stand point (or it might be an improvement), but if the point is to share the link verbally and not via a text link [or if doing so will litter the web with broken links], why support direct links at all?
Why not just have an input box on the home page? The user puts in the english word, and you do the redirect.
