Any parents thinking about allowing their kids to ride motorcycles, what safety precautions should be put in place?

I have had my son riding an electric 12.5r OSET (with stabilizers) which has settings on power and throttle response. I have this to be an excellent starting platform. When he was 3 years old the stabilizers were removed, and now he rides with balance.
Now he has moved onto a PW-50 with a balance wheel. Still not sure when to take it off as his feet cannot reach the ground, anybody got any advice / experience with this?