Nope, I meant ARB's. When cornering the cart tilts. With bigger ARB's the car tilts significantly less with smaller ARB's. I used to have rubbing because of this tilt and because when going thorough sharp corners the wheels steer a lot.
So, you are right they have no effect on clearance or offset but might prevent rubbing when going through sharp corners (like you described).
Also another element which is contributing to this is the height of your car. If it is really low combined with a "not big" ARB (such as H&R for example) you will have rubbing when cornering (sharp corners mostly).