Not a good practice. Had a friend get his hitch hit by a pickup truck with a steel front bumper (plow truck). Barely made contact and if he didn't have the hitch in the receiver the guy would have missed him by about 1 inch. But he always leaves it in there thinking t gives him some type of protection when in relaity it makes his vehicle longer. In any case the impact bent the entire hitch assembly and rear frame and it could never be made right. The guys insurance would only pay for a straightening and new hitch install.

After 3 fix attempts he ended up trading the truck in and was out about $2500.

 

If someone is following me too closely I just "wobble" the handlebars a little bit so the bike moves around a bit in the lane. It gives the person behind you the impression you might fall off and they usually back way off. Try it. It works.