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/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.