The Aviation underworld as operated by Al_Qaeda 
Cartel pilots there have been known to stretch an aircraft’s flight range by putting a water mattress filled with aviation fuel in the cabin, then stacking cargoes of marijuana bundles on top to act as an improvised fuel pump.)
This has been a common practice for extending the legs of pressurized aircraft for years, albeit with real neoprene fuel bladders. The Cabin pressure of 3-8 psi squeezes the fuel out to the wing tanks that have only a little more than ambient pressure. Simple no moving parts, just a bladder, a fuel line and a check valve.
true, aside from the glorified vinyl to be eaten by the fuel, and the bails of weed to pressure the fuel into the wing tanks. 
Deglorifying the almighty three holer one drug run and terrorist airlift at a time!