All four #1, #2 and #3 seeds make it to the Sweet 16.
#5 Auburn made it by beating a probably over-seeded #4 Kansas team.
The only real outlier was #12 Oregon who got hot at the end of the year and benefited from #4 Kansas State lost their second-leading scorer who was also their leading rebounder.
I would think that has to be historic levels of chalky-ness.