A hitch receiver can be a solid, reliable spot to attach a strap. With the end slipped inside the square tube and secured with a solid hitch pin, you have an enclosed, robust attachment point. However, you may have less freedom of working angle in this case and may find the strap rubbing against a sharp edge on the receiver. Hitch balls always look like a handy spot on which to throw a strap end. However, they’re a poor choice, as they don’t secure a strap loop well.