Honda does offer an warranty on accessories
All Honda Genuine Accessories are covered for 3 years or 60,000km when installed at time of new-vehicle purchase. Accessories acquired and installed by a Honda Dealer after the initial purchase of the vehicle itself are covered for 1 year or 20,000km. Accessories acquired and installed by a non Honda Dealer after the initial purchase of the vehicle itself are covered for defect in material for 1 year or 20,000km.