If you refer to us, our dump is next to the link on top. The bottle opens from the bottom but that is not any safer or unsafer than with the robot on its wheels. I actually prefer to gas up that way so the robot cant drive off and the flipper points away from me.

After a fight, assuming you need to dump co2 (we are usually empty anyway) and the robot is upside down you would need to turn it over then also, so I dont see how one is safer than the other.