1. Sounds like a typical GT2 fail. Just wait for the sodding exit and go inside. You won't get slid into and everyone loses less. Don't expect anyone to brake for you if you try to go round the outside after the apex.
2. You cut the track limits to pass and made contact. Douche much?
Blue flag in multiclass racing means: "There is a faster class in a better position approaching". It doesn't really mean anything else. Get overlap before turn-in or wait for the exit.
If they aren't weaving or taking defensive lines to actually block you, it doesn't matter if you lose time or positions, it's racing.
Predictable = stay on racing line, you go around them (see: Le Mans for instance). If by "let us pass" you mean "move the **** over" then no.
There's no live telemetry, but single player laps can be recorded and output to a RAF file that can be viewed by telemetry programs such as the ones found on lfs.net, and LRA (http://www.lfsforum.net/showthread.php?t=20056).
Cargame doesn't spec for slow lap times, there is a limit but it's for a PB to be saved in AIRW.
Personally I wouldn't want to jump through annoying hoops just to play online. The problem isn't so much that players are dangerously bad, but that they're willing to make others suffer for their driving. Either a player understands to not be douchebag by staying out of the way and playing it safe in general, or they don't and I don't want to associate with them based attitude alone, never mind the driving standards.
Srsly, all it means that if you defend the inside line, you can come back toward the outside in order to take a corner as long as there is a car's width of space left for the attacking car. If you move so far back to the outside that the outside 'line' is blocked, you blocked twice and will burn in righteous fire for all eternity.