Download Error - Policy Restriction - audio and video

I've noticed on IOS 11.2 (assume it's on all IOS 11?) that if I try to download audio or video files of some formats they are not allowed by iOS.

For example, if you attempt to download an mp3 audio or mp4 video from http://www.sample-videos.com/ using a file download application (there are many varieties) on iOS, iOS produces the following error message:

Download Error

In compliance with Apple's Policy, audio and video content cannot be downloaded without authorization.

How does one disable this, or get authorization? This works on iOS 10 devices.