As a Vascular Surgeon dealing with trauma for 33 years I agree that although not ususally necessary, a tourniquet is very useful and almost never harmful if removed within a couple of hours (or more). Direct pressure almost always works but often people put a bunch of gauze on a wound and apply pressure with their palm which usually allows a person to bleed to death without squirting on you. Even one or two fingers deep in a wound on the vessel itself stops most bleeding (for extremities). Tourniquets do cause severe ischemic pain to limbs- but don't take them off until ready for the operating room (in most cases) unless another means of control is available.