> I don't see how you can say that this piracy detection fails occasionally. What is your reference?
Some games refuse to install when CD emulation software is installed on the computer. Some games refuse to run when the CD has minor scratches. Some games refuse to run if they can't reach the authentication server. Some operating systems want to be 'reactivated' when they detect one too many hardware changes.
I don't know enough about Steam to tell you where its failure points are, but it's far from the only DRM system in town.
If, in any of those cases, the software stopped throwing an error (which is already quite annoying) and instead started to sabotage me quietly, I'd consider legal action.