EVERY time I had to tow my car, I had to remove the front bumper. Even than, the lower "north/south" bar would hang up on the flat bed. Also, just like Mike mentioned, every time I had it towed, the driver had wood planks to lessen the slope angle.

To make it easier for me to remove the front bumper, I removed the bolts that anchor it to the fender and used zip-ties. So I could cut them when I needed to take the bumper off and kept a pack in the trunk.