ability to compare authority section only for NODATA and NXDOMAIN answers
I envision a new check which will compare authority section only if the message contains is NODATA or NXDOMAIN answer. These could be two separate checks sharing code to compare authority section.
Beware: Answer section can contain CNAME and DNAMEs + their signatures and the answer as a whole can still be clasified as NODATA or NXDOMAIN.