It would be a good idea for tourniquets regardless of what condition the lower extremities are in- they are NOT written off just because a tourniquet is applied!. Bleeding that can't be controlled by direct pressure (like, say, if the bleeding site is trapped in a Farm Machine of Death) is good enough reason to go that route.
Kill the power, apply tourniquets if bleeding is still active and heavy, oxygen, titrated fluids, pain relief, blankets, extrication by qualified personnel.