I like this very much.
A question: Sometimes it is necessary to "ghost ride" another bike(ride your own bike, while guiding a second riderless bike with one hand). Do you think your invention could be ghost ridden easily by grasping the back steering handle?
Ghost riding is not so easy or safe. It requires grasping the empty bike by the handlebar or stem, which is tiring and needs fair concentration. Perhaps your solution would allow more stable ghost riding?