Standard 3 states that an activity is considered to be related to the business lines of an ineligible company when the content provides “any opportunity for the individual to insert commercial bias towards the products of the company”. They advise erring on the caution when determining relevance, since the protection of the learners should be prioritized over the inclusion of faculty members.
Overall, the ACCME states that the content drives this decision moreso than does the profession or area of specialization. You can find more information and specific case scenarios in their online guide. (Examples of Content that Is/Is Not Related to Ineligibility)