"Brilliant Bag Bungee!"
Having read the negative comments regarding this, I thought I would redress the balance. I have had one of these for years and it has travelled all over the world with me - I wouldn't be without it! Provided you tighten the elastic strap sufficiently and thread it through the upper bag handles before looping over case handle, there is absolutely no problem. If sometimes you are slightly overloaded and it has a tendency to tip, just be aware of it and prop it up against something - your own leg will do. It is no big issue.