I wrote:
Roy> I concur. Purely pragmatically, many people will want to
Roy> check both SPF and IETF-compliant Sender ID. Being able to
Roy> fetch both with a single query is therefore beneficial.
I replied without thinking it through; compliant implementations will
check SPF2 first, so the gain I was envisaging does not exist. In
fact, there's a loss in that you potentially fetch the Sender ID data
twice, once in the SPF2 lookup, and once in the TXT lookup needed for
SPF checks.
However, I'm against using a prefix with SPF2 records. It would be
pointless as an attempt to avoid a clash with other uses of SPF2
records, and as others have said, wildcards are unlikely to be useful
in either case...
I'm neutral as to whether TXT records should have a prefix, but it's
probably simpler to put SPF2 records and TXT records at the same
place.
-roy