The consumer may not have a cause of action for trademark violation if they buy counterfeit product (as you say, it's not their right to enforce) but the consum

The consumer may not have a cause of action for trademark violation if they buy counterfeit product (as you say, it's not their right to enforce) but the consumer has other potential causes of action against the seller of counterfeit goods, including but not limited to: breach of contract, unjust enrichment and deceptive trade practices. Moreover, there are significant issues related to the tort of defective products, say you buy a counterfeit apple branded iPhone charge, if said charger catches on fire and burns your house down (and the charger itself), then based on preponderance of the evidence Apple could be found liable as the manufacturer of the counterfeit defective product.