User blog comment:Jimeee/Skyrim 1.9 beta update adds Legendary difficulty and raises level cap (Updated Apr 8th)/@comment-3337232-20130305034749/@comment-4709478-20130317190421

Anywhere between 60% to 70% of the Couriers i've seen only were dressed in a hat. So, I agree with you on the "rare" part of their statement.