That is why I made the video. If you want to see how, watch it (it is about 1 minute).
Model 3 Rollaway
No, I did nothing like that.
No, the risk is isn’t gone, of course. But older children have more control of their actions, and better understanding of consequences of those actions. There is substantial additional protection to having a child who has some awareness of safety issues. For example, you might trust a 5-8 year old (who had been trained and watched previously) to cross a street by themselves. But you would never trust a 2-year-old to do so.
The small child in this case who could “drive” the car would not even be trying to drive the car - he would simply be flailing or clambering around in the footwell, and it would potentially take less than 5 seconds for acceleration to result.
I don’t think you were actually referring to creep mode, but for clarity:
Note that the video was done with creep off, but it does not matter whether creep is on or off; everything behaves the same way. The only difference I found is that a car in creep will move forward about one foot prior to automatically shifting to park, after the brake is released, IF the accelerator is not pressed.