A contractor does not have employees therefore he does not have to have workers comp ins. Owner of the building insists that he have wc ins. His subs are all independent contractors. If he is forced to get wc ins. to cover independent contractors and one of them gets injured on the job, will wc ins. cover those injuries or will they not because they are not the contractors' employee?
Merely having an insurance policy does not mean the insurer will pay for anyone not related to your company. If the people hired are really indepenent contrators, then they would not overedby his WC insurance.