[Al Skierkiewicz]

There is no real damage that can be done to speed controllers from pushing the robot if the robot is turned off. Each of the speed controllers has reverse diodes built into the FETs that are part of the output circuitry and these diodes pass current generated in the motors back to the 12 volt buss. However, you cannot possibly push at the top speed of the robot, so it is unlikely you can generate enough voltage to exceed the 12 volts. You will see the LEDs on the Victors turn on and you may see some other indicators come on while pushing. When you push, you are generating voltage similar to the robot in "coast" when the throttle is zero.