Is Chandler heavy enough to drive the lawnmower?

Geoff thought it would be fun for Chandler to try and drive the lawnmower, he left him a small patch of grass in the front yard. After full safety and driving instructions he let him go. He was doing fine, I was a bit surprised at how well he seemed to be handling it. Then "bang" what the heck was that. He tries again!Again he is driving smooth and then the mower starts to stutter and "bang" again. What the heck is going on? This never happens when Geoff or I drive the mower, and then we realize...a safety factor has been built in to the mower, if you get off the seat it shuts down the mower. Well Chandler is so light that the mower wants to shut down but he is pressing on the gas! Lucky kid it will be awhile before we can make him mow the lawn!