If you mean striking through some sections in contracts too, but wouldn't you have to do it in both copies to have some level of confidence? I cannot imagine you can do this with, say, an ISP contract where you don't agree with some clause.
In the past I've had contracts reprinted after pointing out errors in them.
If it's got my physical signature on it, I've blacked/crossed out the offending sections... recently, even an "online" contract had the option to blackout portions, which I thought was a pretty cool feature.
So, yes, if it's a copy with my signature, it has the offending pieces crossed out.
In the past I've had contracts reprinted after pointing out errors in them.