Thanks - I will post the results here, even if I might have no case. I admit that I booked with UA flight numbers with the express intent to get the UA 100% miles for an S-fare, because that is my honest interpretation of the information that's publicly available.

I'm not sure I agree with your assessment on UA acting only as a travel agent - doesn't codeshare imply a deeper involvement? I'm certain that had I called LH in case of problems with the reservation, they'd have sent me to UA - "Sorry Mein Herr, zis is a United ticket you're holding....". Ugh.