Ok... tell me this.

How are you going to electrically "Ground" an airplane when about 90% of them are made from foam, fiberglass, and balsa wood. The only things that conduct electricity anywhere "decent" (besides the electrical stuff and metal parts) is the carbon fiber in the airframes. But those are not really oriented to build a "common" ground plane that connects each piece of carbon to the next.
Most of the tanks are mounted to Wood structures.. last i checked wood SUCKS at transmitting electricity. Rubber/ tygon/ poly tubing isn't exactly the greatest either at transmitting electricity either, which is what most of us use for fuel and air lines..

Good intentions are probably intended, but its not just as simple as putting an alligator clip to the airframe with a copper wire going to a ground "stake" in the ground. Not to mention in the full-scale world, grounding of the airplanes during refueling is done b/c they are pumping fuel into the tanks a hell of alot quicker than we are, so they have a higher chance in building a large electro-static charge.