They (whoever 'they' are) say it needs to be securely attached to something other than the hitch. Why? If the hitch breaks and stays with the trailer, the cord would not be pulled to set the brakes. Many do attach them to their hitches, however.
Mine is connected using a steel carabiner through a hole in a bracket (body or bumper, I don't recall) above my TT hitch.
Sherm & Terry w/rescue Eydie (min Schnauzer) & Charley (std Poodle)
SOLD:2015 Jay Flight 27RLS, GY Endurance (E), Days: 102 '15, 90 '16, 80 '17, 161 '18, 365+ '20
SOLD: 2006 Ford F350 PSD, 4WD, CC, LB, SRW, Camper pkg., 375,000mi
Full timing: Some will think you're crazy, some will be envious, just enjoy the freedom!