Some do, some don't.
My Spartan K3 won't actually raise the tag, but there is a switch to dump the air from the tag suspension which will unload the weight so the tag won't drag as much making sharp turns.
Other chassis will actually raise the tag off the ground, again for close quarters maneuvers.
2008 King Aire 4562, Spartan K3(GT) w/ Cummins ISX, Motosat HD-SL5 w/ SWM-8, Multiswitch, HR34 Genie
2014 Jeep Grand Cherokee Overland 5.7L V8 Hemi w/ Blue Ox Aventa LX Tow Bar and baseplate, SMI Air Force One brake