FIRST investigated the drag chain/wire concept a few years back. Apparently it creates more problems than it will solve.
http://ftcforum.usfirst.org/showthre...ull=1#post7994
Also compare the FTC robots to FRC robots. The FRC robots 'mass' (size, bumpers, larger frames, etc) allow this work where as FTC it is a great concept but the 'mass' isn't there.
What happens is all the robots drive around. The wheels are van de graff generators. With omni wheels, each roller is an additional generator. Treads also suffer being 2 large VDG generators. The charge is translated into the frame and becomes a leyden jar.
So each robot has varying charges. When robot contacts robot or field elements, discharge occurs where the charge tries to equalize. This results in a robot being locked up sometimes. Higher fidelity (intense gameplay) matches can see this happen more.
Simple solutions involve isolating your electronics from the frame. You can take your pick but simple clear coat or powdercoating works. Even electrical tape on the back of your motor controllers can take a bite out of things.
Other factors affect ESD. If the humidity is under 30%, the risk goes up. In winter, cause air is heated up mechanically water is cooked out of the air so it gets drier. Winter and snowy places also experience higher static risk. If you're fields are on tarps, that adds another factor raising the risk.
I could go on further. Bottom line is you're fighting an uphill battle in an avalanche. Best of luck and don't use the drag wire.