I buy things based upon what I deem to have endurance to get the job done. I have never had a warranty issue on the many racks, bike, motorcycle or carrier in my over 50 years of carrying experience. I have never had to trash one either.
I am pretty confident that Swagman does not recommend specific carriers as strictly a liability disclaimer.
What carrier would recommend aftermarket tie downs? Sales would be zip! We as rv'ers have to modify based on experiences and need.
As previously stated, my "not recommended" carrier has carried our 2 bikes over 4,000 miles across the roughest roads in America. Never any issue after learning how to secure them.