I don't know how my description is wrong other than not specifing any gear other than 1st.
Well going from say a 14:1 to a 1:14,is a big difference, because you are spinning the motor with the wheels instead of spinning the wheels with the motor, so the motor spins faster with a smaller pinion with all other things being equal. This produces higher voltages that could possibly damage the ESC. The motor is acting as a generator at this time, and it's voltage is proprotional to it's RPM.
The question was:Higher pinions = safer MMM's? Or no? Someone's lying....
Jeff