We all have to take responsability for our actions as an adult we have choices. Kids on the other hand place their trust in us, to place his own son in such danger shows a complete disregard for his sons welfare. Would he have put a loaded gun in sons hand and left him alone to play with it.
I have no sypmathy for this idiot. If it stops one biker placing his child in such danger then six months is well deserved. Mind you none of the bikers I know have shown the slightest sympathy for him every body has roundly condemned his actions.
When riding 2 up I always lower the speed and switch to a higher sense of awareness. You have to be aware of what your passenger is doing and how they react to the bike.
Just glad it did not go horribly wrong speeding up un the wet goes against everything you learn about riding.