Occurs to me that counteracting this problem might be one of the strengths of 3D UIs, such as we might have to look forward to in AR systems, or with display ad

Occurs to me that counteracting this problem might be one of the strengths of 3D UIs, such as we might have to look forward to in AR systems, or with display advances. Untrusted content can literally be loaded up and restricted to exist only 'inside' a chrome box, making its provenance clear. Of course, chances are that we'll get carried away with the possibilities of allowing AR web browsers to create arbitrary objects in the AR space long before we realize what a terrible idea that is...