I discovered this old discussion thread while researching an L fare class ticket I bought BRU-CDG.
I don't wish to re-hash many of the strongly-held opinions expressed in this thread (I disagree with many of these), but I can add the following new observations:

- as long as AP has certain code-shared fare classes which accrue no miles, then AC passengers have zero reason to pay revenue fares on non-AC segments;

- since # Star Alliance partners do not disclose this information prior to buying a ticket, then a prima facie case of misrepresentation and/or class action is needed!