Last summer my Auntie got pulled over for her truck being to high. The bumper couldn't be no more than a yard of the pavement of the road, is what she said the cop told her. But she just got warned so she paid no mined to it, just figured he was jealous.
Then my brothers dad had problems with his redneck 4x4, a ElCamino on a full size Chevy frame running 44s, got him for the bumper being to high and not protecting the rear tires in case he got butt poked, so he had to had a second bumper down lower to guard the tires.
This I think is the main reason in the height issue.