Central claim
Restriction must be proportional to harm and evidence.
Applying the Proportionate Refusal Framework, this research argues that automated restrictions in additive manufacturing are ethical only when the strength of the intervention is proportional to both the severity of the threatened harm and the reliability of the system’s evidence.
Machine-level refusal
Refusal requires more than resemblance.
Complete machine-level refusal may be justified when a print job presents a well-supported risk of grave and difficult-to-reverse harm, such as the unlawful production of a weapon, or when a controlled safety-critical manufacturing system can verify that a part lacks required authorization.
Refusal is not justified merely because a design resembles a protected product or contains a recognizable trademark.
Why context matters
Geometry cannot settle the legal question.
Trademark infringement depends on unauthorized use likely to confuse consumers about a product’s source or sponsorship, while copyright exceptions and defenses depend on circumstances that cannot be determined from geometry alone (United States Patent and Trademark Office; United States Copyright Office).
A recognition algorithm therefore cannot reliably infer whether a user possesses a license, is conducting research, is repairing an owned product, or intends to sell an object deceptively.
At the same time, counterfeit medical, electrical, automotive, aviation, and defense components may endanger users as well as harm rights holders, so intellectual-property-related risks cannot all be dismissed as merely economic (United States Patent and Trademark Office).
Proportionate Refusal Framework
The response must rise with the evidence and harm.
An ethical system must instead use graduated interventions: hard refusal for high-confidence threats of grave harm; warnings, authorization checks, or provenance controls for ambiguous and supply-chain risks; and ordinary platform or civil enforcement for lower-risk intellectual-property disputes.
Every restriction must demonstrate net harm reduction, protect privacy and lawful use, provide explanations and appeals, and remain subject to independent audits and narrowly defined public rules.
AB 2047 therefore serves as one demanding test case—not the subject of the entire research.
Firearms present the strongest argument for refusal, while counterfeit goods reveal why the same restrictive infrastructure must not expand without new evidence and proportionality analysis.
Four supporting theses
The argument’s roadmap
The four propositions are paired into two connected stages: judging whether refusal is warranted, then designing and governing the response.
Judging the proposed refusal
Severity and Evidence
The fact that an object may be illegal or rights-infringing does not automatically justify machine-level refusal. The intervention must correspond to the probable harm: illegal weapons and unsafe counterfeit components may warrant stronger controls than consumer replicas causing primarily economic or reputational harm, but only when independent testing demonstrates that the restriction will reduce that harm.
Context and Respect for Persons
Geometry recognition can identify resemblance, but it cannot by itself determine authorization, commercial intent, fair use, repair, research, or other legally relevant circumstances. Restrictions based only on similarity therefore risk treating every user as a suspected wrongdoer and must preserve privacy, interoperability, and legitimate uses.
Designing and governing the response
Graduated and Less Restrictive Responses
Ethical control should not be limited to the binary choices of printing or refusing. High-risk jobs may justify refusal, while suspected intellectual-property violations may be better addressed through warnings, license verification, quantity limits, digital signatures, provenance records, or human review. The least restrictive effective measure should be selected for each category of harm.
Accountability and Scope Control
Because the same infrastructure designed to block firearms could later be expanded to trademarks, copyrighted designs, replacement parts, or manufacturer-imposed commercial restrictions, refusal authority must have published limits, independent audits, meaningful appeals, periodic reauthorization, and safeguards against unilateral expansion by governments, manufacturers, or rights holders.