(It's no good tying stuff on with rope. I know from long experience that rope works loose from the vibration of the scooter. Bungee cord takes up the strain.)
Ethene devised an ingenious safety cord. It's a length of thin steel cable with an eyelet at each end. We each have one and when we stop for short times, like for lunch at a restaurant, we'll thread the cables through the handles of our bags to prevent access. One of the small disadvantages of scooter travel is that there's not much lock-up space for your luggage.
Now we're all set to go.
