i've also noticed people taking corners a lot slower than necessary, creating a backup behind them.
conversely i've seen guys take stupid chances so they can get around someone and alomst (or actually) cause a wreck. it happened to ghostman in our first race and the guy ran right into him.
i don't think it's necessarily inappropriate to pass on the corners but i prefer to wait and pass in other places. i try to use fast cornering as a way of putting a gap on someone or closing a gap, but it's not where i'm gonna try something risky.
i think you should go with your gut. if you feel like you're doing something wrong, you might very well be. maybe find some of the guys you pass after the race and say "hey, i'm trying to get a feel for what's cool and what's not, what did you think of that corner?" and try not to rub it in if you end up beating them
