The 5 Series E34 manual has been floating around the net for a while. In fact, I found out about it from someone here
I didn't know that BMW had any relationship to Bentley Publishing. Do they (and other car co's) license to Bentley? I doubt it.
I've noticed that older BMW tech manuals are freely available online for 70's and some 80's models. I figured that at this point, BMW didn't care anymore. But maybe they just don't enforce it. What do they have to gain by doing so or lose by the existence of this information out on the internet? Esp. the 70's and 80's stuff.