What, nobody raises 'em high enough for the tires to clear the floor? And what about jobs requiring removal of the wheels? Chocks are to me most useful when only one end of the vehicle is raised, and 2 wheels remain on the pavement.
Jack stands need to be properly located, sturdy enough for the particular vehicle, and installed straight such that they cannot tip and allow falling off.
Just my thoughts. BTW, I got a good tip from a neighbor recently, regarding driving a vehicle up on ramps/supports. These things often slide away as the tires try to climb onto them. If a 4X4 is being worked on, placing it in 4WD will aid in climbing the ramps, especially if normal drive wheels (rear, probably) are not on a fairly rough surface. He added that he HATES ramps......I'm inclined to agree! imp