As they're operated by mere mortals too, you may find one time that you're unable to reach your destination on a charge thanks to a miscalculation, or you've parked somewhere you probably shouldn't have. In such scenarios, you'll need to have your car towed to somewhere more appropriate.
Only sometimes, you shouldn't have it towed.
Some electric cars, unlike their gasoline or diesel counterparts, don't have a neutral position in the transmission. They can go forwards or backwards, but when they're not doing either the motor is still connected to the wheels - it just doesn't have any power driving it.
The neutral position in a regular car means that should your car need to be towed to an impound or recovered, it's fairly simple to do so and the car can be towed freely without rotating transmission or engine components. This is not the case with an electric car - when the wheels turn, they'll turn the motor with it and this can result in damage to the motor. Particularly in vehicles with a liquid cooling system, turning the motor at high RPM without this system working can overheat the motor to destruction.
It's not all bad news though.
Some EVs won't have any problems in this sort of situation. Firstly, front-wheel driven vehicles such as the 2011 Nissan LEAF and 2011 Chevrolet Volt amongst others, send their drive to the end that would be aloft during towing, so there's reduced risk. In addition, both vehicles have a neutral mode for their transmission, disconnecting the motor from the drivetrain.
2011 Nissan Leaf
Both GM and Mitsubishi recommend flatbeds rather than towing for the Volt and 'i' electric car, though curiously Mitsubishi says that if the rear-wheel driven 'i' must be towed, it should be done with the front wheels aloft.
The moral of the story is that before you have your car towed for any reason, consult the owners handbook to confirm the recommended method.
As for independent towing firms, we can only hope that as EV usage increases the parking attendants will have undergone appropriate instruction. Even if you're unlucky enough to have your car impounded, you should at least be able to rest easy knowing it wasn't damaged in transit.