Robot fighting has the charming legal advantage that everyone knows the machines are supposed to hit something. That does not make liability simple.
A combat rulebook can define a legal strike, a standing count and a repair timeout. Tort law, contract law, product liability and venue safety ask different questions. The interesting cases begin when a failure crosses the boundary of the contest.
Consent has a perimeter.
Competitors can consent to risks within a sport. Spectators did not consent to a seventy-kilogram robot entering the seating area. URKL's rules reflect that intuition through fencing and prohibitions on sharp, penetrating, high-voltage, fire and chemical attack systems. The arena has to contain foreseeable energy.
A waiver is not an engineering control.
Waivers can allocate some risk and document assumption of known hazards. They do not strengthen a barrier or reduce stopping distance. Legal architecture should follow engineering architecture: identify hazards, reduce them where practical, disclose residual risks and preserve evidence.
Software complicates causation.
If a robot unexpectedly crosses a boundary, was the cause operator input, a software defect, sensor failure, network interference, mechanical failure or a prohibited modification? Those possibilities point toward different responsible parties. Logs, approved software versions, maintenance history, inspections and control inputs become legal evidence.
Existing standards are reference points, not combat law.
ISO 13482 addresses personal-care robot safety and physical human-robot contact; its scope is not humanoid combat sports. A revised service-robot standard is under development. Hazard concepts are relevant, but compliance language must match the actual application.
Robot fighting needs legal architecture that follows the energy beyond the ropes. Competition rules, waivers, barriers, emergency systems, software provenance, maintenance records and incident evidence should be designed together. This is issue analysis, not jurisdiction-specific legal advice.