Yes, if you are not covered by workers compensation:
Let’s take a look at the typical exclusions for Worker’s Compensation
Any condition for which benefits are recovered or can be recovered either by any workers’ compensation law or similar law even if You do not make a claim for those benefits. If there is a dispute or substantial uncertainty as to whether benefits may be recovered for those conditions pursuant to workers’ compensation law or similar law, we will provide the benefits of this plan for such conditions, subject to our right to a lien or other recovery under section 4903 of the California Labor Code or other applicable law. Specimen Policy Exclusions Page 105 * if you are covered by Worker’s Compensation Page 119
I do not see any exclusion that says that if you are doing something and getting paid, it’s excluded.
Group Medical Plans will typically make you sign off that you are excluded under the Worker’s Compensation Laws.
Blue Cross Employer Medical Application Section 12
Definition of employee CA Labor Code §3351