"if they achieve this goal, they can argue that anyone who provides an unencrypted copy of content must have violated the DMCA (which has provision against tampering with encryption)"
How does that help them, though? Anyone who provides an unencrypted copy has infringed on their copyright, so HBO can go after them on those ground whether or not they also violated the anti-circumvention provisions of the DMCA. It seems to me this would only be useful if they think they can actually prevent people from circumventing their DRM.
How does that help them, though? Anyone who provides an unencrypted copy has infringed on their copyright, so HBO can go after them on those ground whether or not they also violated the anti-circumvention provisions of the DMCA. It seems to me this would only be useful if they think they can actually prevent people from circumventing their DRM.