As said.. depends on the series. Looking at the 2 extremes.. BTCC and NASCAR.. BTCC has a high level of tolerance towards contact, NASCAR however sparks off 20 laps of full-course yellow (even if someone just farts in the wrong direction
). An intermediate series in this respect I'd say would be the Aussie V8s where there's often some contact but not nearly as much as BTCC.
I think contact is fine (I don't race open-wheelers.. but in those series, it's somewhat of a suicidal move in most cases for obvious reasons) providing it's not deliberately trying to put someone out of the race. In LFS however, this isn't always possible due to the collision detection. For example, I made slight contact with mouni from SCCC the other night in a race as I dived down the inside of the tight left-hander at AS3. I tried as hard as I could to keep well within an inside line but on exit, clipped his door with my nose. My car didn't react at all, not even a body shake.. seemed nothing.. but looking in the mirror, LFS had made enough of a meal of it to push him pretty wide.. which certainly wasn't my intention.. a racing incident IMO but didn't feel "pleased" that that's how I won the corner as I aim to be as clean as possible.
In short, contact is fine in tin-tops, but you have to use common sense to determine the extent of what is acceptable.. IMO anyway.
Regards,
Ian