I haven't had to do any kind of security cable lock yet, but the way Clyde's friend did it would surely be the best way. I might need to in March, so I should get on that! I do use safety chains from the carrier to the hitch: just in case something
does break during a trip, I don't want to lose (or loose!) my tires and wheels.
I was in the basement this morning shot a couple pics of my carrier (try to ignore my kids' "art" on the floor from 15 years ago...). It's the same one Clyde's friend uses. You can see the wheel chocks I added. I also forgot to mention that I added two simple deflectors so the car's exhaust wouldn't hit my tires. It's probably not an issue, but I just wanted to make sure the tires don't get any warm/hot spots during a drive.