Ah, the shared namespace (annoyingly) explains it. I don't see how
they're related at all, especially given you you can use a different
email to sign up for Google App Engine. Of course collisions are
going to occur left, right and centre.
Anyway, I've pointed my own domain at the app anyway, so as you say,
it doesn't really matter. It's just slightly annoying.
Cheers,
Shane