[Martin Smith]

There is no particular penalty for failing to start a race (complete 2 laps). You simply get no points and the consequent ratings hit.
What you're asking is that when you DNS a race you should get last place points. Or maybe your race shouldn't be counted at all, as if it never happened? I think it's pretty easy to see why those scoring methods can be exploited for the wrong reasons.
But this mehod is more like in real life; if you fail to do something for reasons outside your control, you still suffer the consequences. If that enrages you maybe you should try anger management sessions?
Also, what David said.

Martin, there is considerable extra penalty for DNF, on top of what you would get anyway for finishing last. Otherwise, why would I have written the post to begin with?

If you compare the result of a DNF with the results of a last place finish then of course it will seem like a DNF is an extra penalty. That's because they're almost opposites.

If you want to suggest that disconnects should be awarded last place then fine, then there will never be any DNFs and as I said, that can be exploited. For example someone could sign up for a race and then just go to bed. The next morning they wake up with a rating boost and lower incident rate.

As it stands we get 0 points for a DNF, which isn't special; many series around the world score this way. And with that 0 points we get the same hit to our rating regardless of whether we finished the race or not. So that's not special either.

One possible way to minimize the penalty and also minimize the exploit might be eliminate DNFs as you suggest, but only award 1/2 points to people who don't complete 2 laps.

The bottom line is that anyone who signs up for a race should at least try to compete in it. If it's due to reasons outside our control, then welcome to life.