| 	lookup ip6.arpa;
| 	if (not found)
| 		lookup ip6.int;

It might be worthwhile considering a stderr message from the resolver
library, urging a migration or duplication in the ip6.arpa domain.

Yes, this annoys "innocent" people who do lookups into zones they
have no administrative control over, but it could be in the form
of "<some warning preamble> (if you are not the zone administrator,
please run the following command: update-zone-reminder `host -t
soa xxxxx.ip6.int`).  This will send a polite upgrade suggestion
to the zone contact."

The other possibility is to use the venerable technique (UUNET was
doing this in 1989) of terminating connections to e.g. ftp and
other servers with a similar message when the initiating client
lacked proper A/PTR RR symmetry.

I realize this type of radicalism will meet with negative responses. -:)

	Sean.