Excellent point – I should probably have said mainstream fiction or general/non niche publishing house or something similar. Tech, while not a small market is specialized enough to not threaten entrenched publishers – unless O'Reilly wants to branch out into fiction, etc.
Also, the simple idea of putting your name and address on each page is pretty good low-tech copy deterrence, IMHO. I didn't know about that – thanks for the insight.
Relatedly, it's about simply making people choose one of three options (at the moment): 1) Don't copy it 2)Be okay with everyone knowing your name – i.e.: take a stand and flaunt your disagreement with copyright law or 3) Do a lot of manual work to scrub your name off (even harder if they're PW locked).
Regardless, I like it because it's simple and it embraces the new realities (and abilities) of digital distribution. They could never do that with mass-market books 10 years ago, but now, it's trivial to do with on demand pdfs.
Pakt http://www.packtpub.com/ and O'Reilly http://oreilly.com/ do exactly that. Pakt's pdfs have your name and address printed on each page.