Humm
the arguments you're proposing are effectively true (also because proven by facts
) newertheless the WM of SW is interesting more for avoiding escapes of intellectual properties (under the form of algorithms or code peices). The most interesting application, isn't in avoiding piracy, but in avoiding stoling of algorithms or similar..
Anyway it's an interesting argument..despite encryption or easter eggs, the most interesting approach is the one using excecution paths to store informations or the dynamics approaches that store information inside the memory or the stack..
Another interesting thing is the classic steganographic (hide text into a text) approach in the source code ..
just for discussion..