If and when they force you to have a connection to the internet on your player, you will then know DRM is potentially in use, and they can take away your access to watch it at any time.In 2015, some slides detailing online DRM for UHD Blu-rays leaked out.
I don't think it was ever implemented (maybe due to the backlash?), but it's definitely something to look out. Physical media might not really be physical in the near future.