I don't supercharge often, maybe once every two or three months. A few days ago, I did. I noticed that when I pressed the button to open the charge port, the car next to me clicked, and the green lights came on. That car was actually done charging (the lights were steady, not flashing).
The point is - All I did was press the button to open my charge port. I didn't press the button on the other car, but the signal was strong enough to trigger the other car.
Tesla Motors needs to rewrite the code for the car, so it doesn't reset charging when a) the button is pressed AND b) the car is plugged in and charging.