AKC Registration Rule Interpretation?

Under what circumstances can a litter be registered without the
signature of the stud dog owner?

Case in point: Co-owners dispute rights to the litter. Go to court.
Eventually settle out of court. Both sign off on litter.

Meanwhile, one of the co-owners gets into a fight with the stud dog
owner, who then refuses to sign off on papers. No written agreement
exists regarding stud fee.

Both sire and dam have been DNA'd.

AKC website says the following:

"The American Kennel Club takes the position that the owner of the sire
is required to sign an application to register a litter certifying only
to the fact that a particular dam was bred to the sire identified on the
Litter Registration Application form on a specified date of mating,
unless there is an agreement signed by all parties concerned in which it
is specifically set forth that the owner of the sire is not obligated to
sign an American Kennel Club Litter Registration Application form until
such time as the stud fee has been paid."

Do they mean that the signature of the stud dog owner is required?
Or that the stud dog owner "is required to sign"?