I think the idea is to limit demo to a really serious trial of the game. FWD, RWD and a open wheel racer, with a track to try them out.
This then means that the users that don't intend to play LFS probbably leave, so it decreases bandwidth, and those that were wondering along the lines of "hmm maybe I'll buy it" have even more reason to splash out. Those who genuinly want to buy the game, but can't for whatever reason, will still be active and play, so it seems that it's a lose (for cheapskates), and a win win for both the users who want to buy the game (because they'll play it anyway), and the devs from the increased amount of S2 licences bought. What "Power by AMD[ARG]" doesn't seem to understand is that many of the demo racers have been playing for (quite possibly) just as long as someone like myself or Boris has, but they have no intention of paying for a game. I know sometimes people can't afford it, but if you save like 5p a day you can have it after a year.
I guess you can still drive BL1r though, just on practise, and use some sort of insim app to either create a grid so you can race backwards without the "wrong way message", with splits and the like, or at least, to get rid of the wrong way thing.