Considering that no scheme like this has been widely deployed,
arguments from authority are not very helpful.
If you're arguing from practice, the practical fact is that at least one
widely used DNS cache, the one in djbdns, doesn't return authority records
so clients can never find the zone cut. This is clearly not what the RFC
says but the author argues (rather vehemently) that it's considerably
faster than what the RFC says and interoperates just fine with existing
clients.
Regards,
John Levine, johnl(_at_)iecc(_dot_)com, Primary Perpetrator of "The Internet
for Dummies",
Information Superhighwayman wanna-be, http://iecc.com/johnl, Mayor
"I dropped the toothpaste", said Tom, crestfallenly.