Also in the article, they test a detector that has to identify a single object in an image that contains two: place an actual toaster next to the banana and call it fooled.
More than that, you can fool models that work completely differently (like decision trees, SVM and kNN) with false data made for the other model, which shows some kind of underlying similarity in there that we don't know yet.
Or maybe just similarity of the training sets?
Humans would consider this a non-interesting exploit.
This detector has to choose a label for an image with two labels. Use something like YOLO2 on this, and the detector will recognize a banana AND a toaster.
Now we do know that compared to humans, these detectors over-react to textures over structure. If you look at the sticker, you can see how it kinda looks like a toaster: the big red blob looks a bit like a toaster button. A generic shape is there, the thing over the button looks like both the control to lower the toasts and the slit where the toasts are.
These classifiers will get better at recognizing structure, especially if we train them against this kind of things.
If necessary, next week these system can learn to ignore these.