I think it was slashdot where years ago there was a comment lamenting the DRM-free digital downloads from purchased O'Reilly products. The user was complaining

I think it was slashdot where years ago there was a comment lamenting the DRM-free digital downloads from purchased O'Reilly products. The user was complaining this wasn't good enough. He actually wanted O'Reilly to publish MD5 hashes of all their works, so he could very his download had no traceable watermarks. To me it was ridiculous he expected a company to do this, especially one of the most DRM-friendly companies to boot.