Figure 3 in the game manual provides a flowchart that Head Referees should use to determine the appropriate penalty for any Violation, including a Violation of <SG8> like the one you've described.
Here's how a Head Referee should work through that flowchart for your example, in which an opposing Robot broke the plane of the opponent's Goal but didn't remove any Triballs:
- Rule <SG8> does have specific guidance for Violations, but they don't apply to this scenario, so we move to the 2nd blue diamond
- The Violation did not change the score, so cannot have been Match Affecting; we move on to the 3rd & 4th blue diamonds
- Because we don't know the larger context of the Violation within the Match and the event, we don't know whether other Violations are involved or if this is a repeated Violation
- If the Head Referee answers 'no' to the questions in the 3rd and 4th blue diamonds, the Team will receive a Minor Violation and a formal warning; if a Team has already received multiple Minor Violations for a rule those Minor Violations will grow to a Major Violation and Disqualification
The only rules that specify Disablement of a Robot are the safety rules (Robot is unsafe, causes damage, or leaves the field) and <SG5> when a Robot becomes Entangled with the Net. Disablement is not a correct response to a Robot that Violates <SG8> or most other rules.