<R4>
Robots must be safe. The following types of mechanisms and components are NOT allowed: Those that could potentially damage Field Elements or Discs. Those that could potentially damage other competing Robots. Those that pose an unnecessary risk of Entanglement with other Robots or the Net. Those that could pose a potential safety hazard to Drive Team Members, event staff, or other humans. Per <G12d>, it is expected that some Entanglement or incidental damage may occur during the Endgame. Therefore, it will be at the inspector’s discretion whether any mechanisms designed solely for use during the Endgame violate any portion of <R4>. In general, if the mechanism in question does not pose a risk of Entanglement or damage during the rest of the Match (e.g., it is demonstrably confined to an intentional expansion during the Endgame), then it will not be considered a violation of <R4a>, <R4b>, or <R4c>. This can be considered a “necessary” risk, in the context of <R4> / <G12>. However, this interpretation does not extend to rule <R4d>. Any mechanism or component which is deemed to pose an unnecessary / egregious safety risk may still be considered in violation of <R4>, <S1>, and / or <G1> at the Head Referee’s discretion.