Following the Layer-2 Addressing analogy means that Ian, here:
If the daily descriptor uploaded to the point
Hash(onionaddr, dailyrand) contained Hash(onionaddr, dailyrand) *in* it (and is signed by the master onion privkey, of course), then tor could/should check that it reached that location through the "right" onion address.
…has essentially just invented what Solaris (for one) calls "IP Strict Destination Multihoming":
http://www.informit.com/articles/article.aspx?p=101138&seqNum=4
-a :-)