yes, for example with device fingerprinting. the Electronic Frontier Foundation has a nice test page online: https://panopticlick.eff.org/ however apple could apply a much simpler filter by checking whether the screen size fits the exact specs of their iphones / ipods and ban any other devices.

then again, you might always access the source directly, circumventing the need for js entirely.

I am not sure related native iOS streaming libraries integrate JavaScript security just to protect iTunes previews.