Macrovision is why you can't tape from a DVD to a videotape. Try it and you get signal distortion generated by the receiving system. Dan's Data claims cheap DVDs, by which I assume he means the $40 models often sold in hardware stores, may not have Macrovision support:
Macrovision is turned on by most commercial DVDs, but you can disable it on many cheap DVD players these days, one way or another. The better cheapo players come with Macrovision (and region coding) turned off.Dan's in Australia, I don't know if this is true in the US. It's illegal in the US to describe how to defeat Macrovision, so Dan can't give details. Heck, maybe it's illegal even to mention that some devices don't have it enabled. Free speech is so 20th century.
PS. Amazon sells some devices that claim to filter out the signal that recording systems rely on to trigger their video distortion mechanism.