1, Just wouldn't work in reality. For Example when i've just joined a race say in lap 5 i'll start to try and get as many positions ahead for a better starting grid slot. So if i come up to a racer who is 0.25 slower than me but I feel I could pull away I would overtake. But on doing this it may take me a whole lap to get rid of the blue sign, which would gain me a black flag even though I am faster and I am not slowing the other driver down.
2, Its a nice idea but sometimes you just can't help it especially if the crashed driver is rejoining on the apex as you come round (hate that) but you are right you should back off the throttle and be more aware. When i've had spins/collisions and someone comes flying around the corner and hits me, there was nothing I could do quickly enough to get out of the way but I still get a whole load of abuse from the person who crashed into me even though they never tried to slow down just a little.
Sometimes I just wish people realise stuff like this happens, we are all humans and make mistakes now and again. (I hardly ever get into situations like that but during the race there is always some argument about who done what and who's fault it is etc. Luckily the devs implemented the glorious - for message blocking)
Andy.