Personally, I have found having lights on a robot helps diagnose problems you might experience in the arena. I had a pair of flashing blue beacons on the top of ToeCutter2 (and the animated pig of course!). They also helped as a reminder to turn the remote fail safe on/off as required, and gave an aid to the state of the electrics in the robot. The pig also helped, as it was in the failsafe circuit too, with visable movement and audible sound, though on a seperate circuit, so if the lights failed/got damaged etc, I still had an additional indicator. Seemed to work quite well all in all.

Jon.
TC2