So is this something that Flex 4K owners need to worry about??
It's mostly FUD. But, the HDHR tuners actually have the necessary certificates and keys necessary for DRM components in ATSC3.
To follow the full discussion and get the actual reality of the situation, here's the thread over at SiliconDust's forum:
https://forum.silicondust.com/forum/viewtopic.php?t=76772