I was told to do the ‘1 car length per 10mph’ rule of thumb when learning and I still try to whenever I can. Its not perfect, but its always in the back of my mind so I am usually aware of I’m getting too up on anyone.

Not sure why OP is balking at the warning on vehicles. Legality aside, sometimes its good to have a heads up. People need to chill the hell out on highways in general.