The developer support shell page needs to use signed variables too. Otherwise, you could pass the variables directly to developer-support using an IMG tag, and not even bother to make yourself site-wide admin.
Barry, thank you for actually doing something about all this discussion! Is anybody willing to port his code to Postgres once he's done testing it?
I personally think this is a security fix, so it wouldn't require TIPing, but perhaps it could be TIPed just to be extra sure...?