I think the solution is not to ask the user for permission but to automatically create an anonymous sandbox that does what the site requests — except that sensi

I think the solution is not to ask the user for permission but to automatically create an anonymous sandbox that does what the site requests — except that sensitive information is faked or reduced. And if a web application is complex and has weird dependencies, it should be necessary to “install” a sandbox ONCE with those dependencies (e.g. needs plug-ins X and Y), and at that time the user can see everything that is being exposed and essentially only has to approve once. It will not work to constantly ask the user. They will just opt-out, or worse opt-in without really knowing or caring what they have done. And usually, they will not know where to go to change their mind later (probably buried in preferences somewhere).