[MasterEric]

It may be the opposite; defense could become quite hard considering how ugly the rules about possession of a ball are.

Specifically, it can be hard to ensure a given bounce is a deflection and not a launch, or a deflection and not herding. See G12 of the rules for more details about this.

Spoiler for G12 of the Game Manual:

G12 An ALLIANCE may not POSSESS their opponent’s BALLS. The following criteria define POSSESSION :
A) “carrying” (moving while supporting BALLS in or on the ROBOT),
B) “herding” (repeated pushing or bumping),
C) “launching” (impelling BALLS to a desired location or direction), and
D) “trapping” (overt isolation or holding one or more BALLS against a FIELD element or ROBOT in an attempt to shield them).
Violation: TECHNICAL FOUL per instance.

Examples of BALL interaction that are not POSSESSION are
A. “bulldozing” (inadvertently coming in contact with BALLS that happen to be in the path of the ROBOT as it moves about the FIELD) and
B. “deflecting” (being hit by a propelled BALL that bounces or rolls off the ROBOT).
A BALL that becomes unintentionally lodged on a ROBOT will be considered POSSESSED by the ROBOT. It is important to design your ROBOT so that it is impossible to inadvertently or intentionally POSSESS an opponent’s BALL.