[Al Skierkiewicz]

To answer your first question,

The other way around. Nothing on the robot can extend outside of the Frame Perimeter...
[R01-2]
The Robot must have a Frame Perimeter that is comprised of fixed, non-articulated structural elements of the
Robot. The Frame Perimeter of a Robot is defined by the outer-most set of exterior vertices on the Robot that are
within the Bumper Zone, which is between 2 and 10 in. from the floor.

AND

[R02]
The Robot must satisfy the following size constraints:

E. no other part of the Robot may extend beyond the vertical projection of the Frame Perimeter (with the exception of minor protrusions permitted per [R01-2]).
If a Robot is designed as intended and pushed up against a vertical wall (with Bumpers removed and appendages retracted), only the Frame Perimeter (or its minor protrusions) will be in contact with the wall.

The whole object to bumpers is to minimize robot damage in collisions with other robots or with field elements.
Emphasis mine.