Well, that's good to know but:
-SAN boot target and zones are different (related) things
-I'd love to know the "why", not only the "what" to do.
AFAIK, zoning is just a security (authorization) method controlled by the fabric.
I can see that doing it based on WWPNs is finer than doing it at WWNNs, also WWNNs are "movable" so to say, so security based on that could be flaky. That's more or less as far as I can see now.
Thanks,
-Carlos