That's not really true. Video upscaling is probably going to be linear interpolation, which is very unlikely to add meaningful artifacts, but an intelligent zoom that tries to add visually meaningful information may change the apparent content.
> Video upscaling is probably going to be linear interpolation
This is probably true of the technology that's currently in the courtroom, but not for much longer, e.g.[1]. Apple have even done research on this[2], although I can't find anything that says it's currently in use on the iPhone/iPad.
Seeing the mess my 4k "smart" TV makes of 1080p video with parallax scrolling (say a car driving between two rows of trees, filmed from the side), I think we're well past linear interpolation in consumer devices with upscaling.
