While there is a pretty clear difference between standard and high definition, I'm sure no one can tell the difference between 1080p and 4K unless they are looking at a gigantic (e.g. 80"+) TV or standing right in front of the TV.
In our living room, if I connect my laptop to the TV (37") and sit ~15 feet (~3m) away, I cannot read small print on the screen and the same for anyone else I know. So it's pretty clear that if the TV was 4K, there's no way I would seeing anything that I wouldn't see with 1080p at this distance.
The DRM is basically nonsense. Who ever can afford a suitably large TV to take advantage of 4K can obviously afford to pay for the titles to play on it and of course it's going to be these paying customers that will treated like potential criminals by this DRM.