Seriously ? What do you think happen when one cam is in and one can is out the bushings are no longer at a 90* to the frame thus putting the bushing on a bind.
But they will be parallel, just on different centers
Whereas pinching them will skew them, with one bolt pointing one way, and the other in a different direction.Now they will be attempting to move the shoulders of the steel frame brackets. Since they cannot, they must flex if rubber, or wear out if poly.