Thanks for doing that. I was on a FIRST Robotics team and got my lesson the hard way. Was debugging some driving code sitting next to the robot which was up on blocks. The code wasn't working so while ponding why my hand ended up close to one of the wheels when suddenly it started to work, driving the motors at full speed which swept my finger up into the drive chain. I got real lucky and only lost a small flap of skin, but I learned the battery always needs to be disconnected before any hands get near the robot.