OK, let me comment on the tow rope as pictured in the YouTube video.... Extremely dangerous! You should never hook two bikes together like that. If the rear rider happened to veer off, the rope will take them down. It can be done with a tow rope by wrapping the rope once around the handle bar of the rear rider, so the rider holds the wrapped rope with their hand and can let go when in trouble. This requires an experience rider to begin with. To attach a tow rope to a child's bike like in the video is stupid and cruel.